Georgius Gemistus Plethon

Huck

Interesting speculation about "Themistius", but the Catholic Encyclopedia article is clearly wrong about the inscription saying "Themistius". It's just "IEMISTII BIZANTII", it's certainly an "I" not a "TH". I assume it stands for the pronunciation "Jemistos" (soft g before the e).

"The remains of Jemistus of Byzantium, Prince of the Philosophers of his time; Sigismondo Pandolfo Malatesta son of Pandolfo, Commander in the Peloponnesian war against the king of the Turks, on account of the immoderate love of learning with which he burns, has them brought here and placed within. Accomplished 1465."

Well ...
the "wrong reading" is naturally clear, I've no doubt about this.

But the speculation says, that already "Gemisthos" is possibly an artificial name, a pseudonym.

Θεμίστιος ... that's Themistius in Greek ... TH is just one letter in Greek
Γεμιστός ... nearly only a change of TH to G (and ιο changes to ό)

In the wandering of the alphabet from Greece to Latin the row of the letters changed from Gamma (3rd letter in Greek) to G (8th letter in Latin) and Theta (8th letter in Greek) to C (3rd letter in Latin). Plethon (very likely) knew this and in his surrounding (if we assume, it was Adrianople) were others with some sense for letter-Kabbala (Jews and Sufis, who used letter-Kabbala with Arabian and Persian alphabet and 28 and 32 letters).

Well, this is - no doubt - very speculative.

**********

I detected this new book description ...
http://www.myriobiblos.gr/texts/english/Constantelos_2.html
... about Scholarius, Plethon and a victim.
 

kwaw

I read "IEMISTII BYZANTII" and think that "I" at beginning (in Latin) is easily "G" (elsewhere, Ieronimo is Geronimo etc.) , so there is a Gemistii Byzantii ... Gemistius Byzantium.
I would assume, that this Themistius is just "wrong reading". Or? Any opinion?

I agree - Themistius is clearly a "wrong reading".

IEMISTII = Gemistus, that is the Byzantine (BYZANTII) philosopher, Georgius Gemistus:

"Born in Constantinople about 1355, died in the Peloponnesus, 1450. Out of veneration for Plato he changed his name from Gemistos to Plethon."


(By coincidence I came across a reference to Themistius while looking for Hankins Calderini' Reference "several Themistian manuscripts were in the Aristotelica collected by Cardninal Bessarion... In 1430 Francesco Filelfo... loaned his manuscript of the Themistius' paraphrase of the Posterior Analytics to Vittorino da Feltre...Later in the century... Mirandola sought the help of Giorgo Valla in obtaining a manuscript of the same work...Ermolao the Younger translated the whole of the the Themistian corpus between 1473 and 1480..." )
 

Huck

Thanks Steve ...

... thinking about Themistius or Themistios and the curious name similarity to Gemisthos, I realized the argument, that Plethon chose the name "Plethon" cause the similarity to the name Platon.

That's just the same or at least similar game with letters.

So, if then "Gemisthos" is an artificial name, there would be another name for the same person before 1407.
 

MikeH

Huck wrote
I detected this new book description ...
http://www.myriobiblos.gr/texts/english/Constantelos_2.html[/quote
... about Scholarius, Plethon and a victim.
Thanks for the link, Huck. I want to draw people's attention to the following in it:
Plethon spent some time in the Sultan's Court at Adrianople. Nevertheless, the view that attributes to Islamic thought decisive influence upon Plethon has little ground for support. Gennadios' writings show that Islam exerted little, if any, influence on him. Gennadios' essay Kata Hellenon as well as his lengthy letter to Oisses reveal that it was Greek religious and philosophical thought rather than Islam that contributed to Plethon's religious development. Milton V. Anastos has rightly emphasized that the whole theory of Plethon's philosophy and encyclopedic knowledge depended upon Greek literature, ancient and mediæval.(6)
True, Moshe Idel speculates that Elisha might have been "part of a school of mystics starting with twelfth-century Muslim Sufi master, Suhrawardi al-Maqtil, called Isharqi (the illuminated)" p. 144 of http://books.google.com/books?id=CX06dsbZ_JIC&pg=PA137&source=gbs_toc_r&cad=4#v=onepage&q&f=false). Idel's source is Bidez and Cumont, Les Mages helleneses: Zoroastre, Ostanes et Hystaspe d'apres la tradition greque, II, p. 21. Anastos thoroughly undermines Bidez and Cumont (p. 279-303) in a very scholarly way, and our current author seems to side with Anastos. I suppose it was possible to be a Sufi without being a Muslim except nominally, i.e. a Bogomil or Manichean in Muslim dress. It happened in Bosnia and elsewhere, according to some. But that gets complicated. Nobody seems to address that possibility.

Hi, Kwaw, I'm glad you've joined us. Hold onto your vol. 1 of Hankins. When I thought I'd lost the library's copy, I looked on Abe Books, and that edition is pretty spendy now. A university library a few miles form me has both volumes, always checked in, except when I get it on interlibrary loan. I posted pp. 92-95 in this thread.

Also, thanks for pointing out the reference to Filelfo's reading of Proclus on Hankins p. 94. The question is whether the relevant fragment of the Chaldean Oracles (about the child and the horse) is in that work, or in a different work of his. One translation (http://www.sacred-texts.com/cla/af/af08.htm: Golden Dawn?) has it as fragment 198, and says it is from "Proc. in Pl. Polit. 380." Another, more scholarly source, is Hecate Soteira: A Study of Hekate’s Roles in the Chaldean Oracles and Related Literature, by Sarah Iles Johnston, 1990, p. 111, which has it as fragment 146, the source for which is "Proc. In R. 1.111.3-11". In her bibliography, the only work starting "In R" is "In Rem Publicam, 2 vols, Leipzig 1899-1901. Is that the same as "In Remp.", (or "In Rem p"?) which you identify as one of the commentaries on Plato's Republic? If not, is "In Rem Publicam" also a commentary on Plato's Republic? Plato's Republic was a hot topic in Milan, owing to the Decembrio translation and application to Milan, and so if it was available to Filelro, he probably would have read it. Then he could have noticed the passage about the child and the horse, which is pretty colorful.

On another topic: Two other means of transmission of Plethon's edition of the Oracles to Ficino in the 1460s have occurred to me. One is from Filelfo, by way of Lorenzo's visit to Milan in 1465. (As I've argued here, he must have at least seen it, to maintain, as he seems to do in the 1464 letter, that Zoroaster originated Plato's theory of Forms. And Plethon was right about it being in the Oracles; he's just wrong about when they were written; like the Corpus Hemeticum, they're really 2nd century or so.)

The second possibility for transmission derives from a passage in Woodhouse, p. 375:
Two other expatriate Greeks in the next generation to whom Plethon's name at least must have been familiar were Michael Tarchaniota Marullus and Manuel Kabakes.[Footnote: Kanellopoulos, ii. 42.] They were close friends and both inclined to pagan doctrines. Manuel was the son of Plethon's most devoted admirer, Demetrios Raoul Kabakes. Marullus, who was born in Achaia in 1453 and carried to safety with his family when the province was overrun by the Turks, was a soldier and poet. He settled in Florence and married a secretary of Lorenzo de' Medici. Neither of the two friends ever mentioned Plethon, but their outlook on life had much in common with him.
Of course Marullus, although in the right place at some point, would have been too young to influence much in the 1460s. I am thinking of the two men's fathers. If the young men were friends, maybe their fathers were. Maybe the families knew each other in the 1460s: why not, if they were both followers of Plethon, and both in Italy (Kabakes senior in Rome 1466, friends with Bessarion, whereabouts unknown between the 1450s and then)? And "Plethon's most devoted admirer," Kabakes (or Kavakes) senior, as I have documented previously in this thread, was a professional copyist known to have copied Plethon's works in 1441, as letters in Legrand's edition of Filelfo's letters (but not by Filelfo) show. Maybe the tie to Florence, and to the Medici, goes back to the 1460s, when Ficino seems to have first seen Plethon's edition of the Oracles.
 

kwaw

Also, thanks for pointing out the reference to Filelfo's reading of Proclus on Hankins p. 94. The question is whether the relevant fragment of the Chaldean Oracles (about the child and the horse) is in that work, or in a different work of his. One translation (http://www.sacred-texts.com/cla/af/af08.htm: Golden Dawn?) has it as fragment 198, and says it is from "Proc. in Pl. Polit. 380." Another, more scholarly source, is Hecate Soteira: A Study of Hekate’s Roles in the Chaldean Oracles and Related Literature, by Sarah Iles Johnston, 1990, p. 111, which has it as fragment 146, the source for which is "Proc. In R. 1.111.3-11". In her bibliography, the only work starting "In R" is "In Rem Publicam, 2 vols, Leipzig 1899-1901. Is that the same as "In Remp.", (or "In Rem p"?) which you identify as one of the commentaries on Plato's Republic? If not, is "In Rem Publicam" also a commentary on Plato's Republic?"

I think all the sources, in their somewhat confusing array of varying reference conventions - are referring to the Commentaries of Plato's Republic by Proclus - or Proclus, In Remp as Hankins refers to it on p.94 (Procli Diadochi in Platonis Rem pvblicam commentarii).

"Proc. in Pl. Polit. 380" is correct, but most sources refer to it as 'fragment 146' not '198'.

Johnston's reference is to Kroll's 1899 edition which is available (in Greek with a Latin introduction) online in several formats - unfortunately not searchable as they are scanned as images rather than text - (the text version transliterates the Greek into gobbledy gook) - but following the references 'Proc. in Pl. Polit. 380' is in Kroll's Volume 1, on page 111, lines 3-11.

Line 9 commencing re: the boy = Η και παιδα etc.,

(I did not have Johnston's reference when I found the text, but managed to find the segment via the reference to 'proc. In Remp. 380' given in various sources along with the Greek text)

http://www.archive.org/stream/proclidiadochiin01procuoft#page/110/mode/2up

If you have trouble recognizing it I include an image of the greek text from Isaac Cory's Ancient Fragments as an aid - which he translates as:

Or a boy on thy shoulders riding on a horse,
Fiery or adorned with gold, or divested,
Or shooting, or standing on thy shoulders,

see p.118/119:
http://books.google.com.tr/books?id...&resnum=3&ved=0CC8Q6AEwAg#v=onepage&q&f=false

Kwaw
 

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Huck

Population in the Osman Empire (capitals)
----------------------------------------

Encyclopedia of the Ottoman Empire
http://books.google.com/books?id=Qj...=7&ved=0CEsQ6AEwBg#v=onepage&q=Edirne&f=false

Edirne = Adrianople
-------------------

Keyword "Edirne", which is the Turkish name for "Adrianople".

800px-BG-1371.jpg


"Odrin" at this Turkish map.

edirne.jpg


******************

Byzanz
-------

composed from
http://en.wikipedia.org/wiki/Constantinople
http://depts.washington.edu/silkroad/cities/turkey/istanbul/istanbul.html
By the 5th century, it held around 300,000 inhabitants; by the middle of the 6th, some half a million. For comparison, Chang-an, the capital of Tang China, may have had as many as a million inhabitants at its peak a century later, and Baghdad, at its peak in the early Abbasid period probably had more than half a million. During Justinian I's reign, the city's population reached about 500,000 people.The Plague of Justinian happened between 541–542 AD. It killed perhaps 40% of the city's inhabitants.
...
In the early 7th century the Avars and later the Bulgars overwhelmed much of the Balkans, threatening Constantinople from the west. Simultaneously, the Persian Sassanids overwhelmed the Prefecture of the East and penetrated deep into Anatolia. Heraclius, son to the exarch of Africa, set sail for the city and assumed the purple. He found the military situation so dire that he is said at first to have contemplated withdrawing the imperial capital to Carthage, but relented after the people of Constantinople begged him to stay. Constantinople lost its right to free grain in 618, when Heraclius realized that the city no longer could be supplied from Egyptian sources due to the Persian wars. The population of Constantinople dropped substantially in size as a result, from 500,000 inhabitants to just 40,000-70,000.
...
Despite a long period of disasters and decline, with its revival in the 9th and 10th centuries the population of Constantinople again swelled, to between 500,000 and 800,000.
...
The Byzantine revival of the 10th and early 11th centuries was short-lived, however. By the 1070s, the Seljuk Turks had defeated the Imperial army and seized much of Anatolia. Not long after, the Venetians gained a strangle-hold on the Empire’s trade. A Western author in the middle of the twelfth century, Odo of Deuil, presents a quite contradictory picture of a city that was “the glory of the Greeks, rich in renown and richer still in possessions,” but one that one that was simultaneously “squalid and fetid and in many places harmed by permanent darkness, for the wealthy overshadow the streets with buildings and leave these dirty, dark places to the poor and to travelers; there murders and robberies and other crimes which love the darkness are committed.”
...
The Venetians had factories on the north side of the Golden Horn, and large numbers of westerners were present in the city throughout the 12th century. Toward the end of Manuel I's reign, the number of foreigners in the city reached about 60,000-80,000 people out of a total population of about 400,000 people. In 1171, Constantinople also contained a small community of 2,500 Jews
...
Relations with Venice and the West more generally steadily deteriorated, culminating in the Fourth Crusade’s sack of the city in 1204.
....
The city never would recover from the devastation of the Fourth Crusade, even though Venetian commercial interests ensured that it would remain an important center for trade with the East during the period of Latin rule which lasted from 1204 to 1261.
....
When Michael VIII captured the city [1261], its population was 35,000 people, but, by the end of his reign, he had succeeded in increasing the population to about 70,000 people. The Emperor achieved this by summoning former residents having fled the city when the Crusaders captured it, and by relocating Greeks from the recently reconquered Peloponnese to the capital. In 1347, the Black Death spread to Constantinople. In 1453, when the Ottoman Turks captured the city, it contained approximately 50,000 people.
By the early 15th century within its great walls the population had shrunk to a few tens of thousands. The chronicler Sphrantzes was very specific about the disparity in forces when Ottoman Sultan Mehmet II mounted the final siege that resulted in the taking of the city on May 29, 1453: “He surrounded the entire 18 miles of the City with 400 small and large vessels from the sea and with 200,000 men on the land side. In spite of the great size of our City, our defenders amounted to 4,773 Greeks, as well as just about 200 foreigners.” The last Emperor died on the walls and the Patriarch, the head of the Byzantine Church, was taken captive.

*************

Bursa
-----

bursa.jpg

http://books.google.com/books?id=QjzYdCxumFcC&pg=PA105#v=onepage&q&f=false

Bursa was taken by the Ottomans after a 6-years-siege in 1326 from the Byzantine empire. Some of the Greek population stayed in the city. Bursa became then the capital.
According this Encyclopedia report Edirne became capital after Bayezid was captured and Bursa was sacked by Timur Lenk in 1402 (other reports have Edirne as capital already since 1365). During these operations in 1402 important items (treasures, papers etc.) were transferred from Bursa to Edirne. It's said, hat Edirne after 1402 took a larger development step, when Bursa went down.
 

Ross G Caldwell

I'm not completely satisfied I've understood everything correctly in this passage, but the sense is clear. Filelfo does believe that the philosophy of "Idea" comes from Zoroaster, but he doesn't cite any writings, just Pythagoras' basis in Magian teachings.

He clearly believes in some kind of "prisca philosophia", but not as Ficino would codify it. There is no mention of Orpheus or the Aglaophemus who was held to be Pythagoras' Orphic teacher.

Filelfo to Dominico Barbadico, 13 April, 1464 (Venice 1502, f. 151v (entire letter, 150r-151v); Hankins 2, pp. 521-22, ll. 250-271 (entire letter, pp. 515-523))

Et huius quidem ideae inventor omnium primus, quotquot aut in Ionica aut in Italica claruissent philosophia, Pythagoras fuisse perhibetur. Secutus is quidem Zoroastren, qui bellum Troianum, ut Plutarchus refert, annis quinque millibus antecessit. Pythagoras enim ut caeteros omnis suae tempestatis, homines, formae venustate, atque praestantia mirifice adeo antecelluit, ut pro Appolline haberetur, ita divina quadam ingenii bonitate atque sciendi studio, cunctis mortalibus superior fuit. Quapropter ubi universam peragrasset Europam, quo undique, quicquid scitu dignum animadvertebat, acciperet, ductus tandem illustri fama sacerdotum, atque prophetarum, Aegyptiorum, profectus in Aegyptum, ubi simul cum lingua omnem illorum sapientiam didicisset, illud etiam intelligere visus est, Aegyptios eximiam omnem disciplinam a Magis, qui a Zoroastre fluxerunt, hausisse. Quare ad Chaldaeos se contulit, quo et Chaldaeos audiret qui astrologiae gloria habebantur insignes, et Magis quos apud illos versari acceperat, congrederetur. Magorum igitur diuturna usus consuetudine non obscure intelligere visus est unum Zoroastren Persen, ut antiquissimum philosophorum omnium, ita etiam acutissimum, sapientissimumque fuisse. Quare ex illa hora, Zoroastris philosophiam amplexus est. Quam postea Plato quoque Pythagoreis usus et auctoribus et doctoribus est secutus. Manarunt in quam ab ipso usque Zoroastre philosopho, quae sapienter et peracute de Idea, scripta a Platone referuntur.

Indeed Pythagoras is held to have been the first discoverer of this idea, of anyone, however many others might have illuminated either Ionia or Italy with philosophy. Of course, he followed Zoroaster, who lived five thousand years before the Trojan War, as Plutarch says. But Pythagoras made himself so preeminent, to all the other men of his time, with beautiful form and outstanding excellence, that he could be taken for Apollo, superior to all mortals, with a kind of innate divinity and spirit of knowledge. He traveled over the whole of Europe, investigating everything that was worthy of attention in its entirety, so that he was admitted, finally, among the illustrious Egyptian priests and prophets, progressing in Egypt, where at the same time he acquired all wisdom in their language, so that he understood that all the excellent Egyptian disciplines which flowed from Zoroaster had been absorbed by the Magi. Therefore he went to the Chaldeans, and heard the astrologers that were held famous among them, and engaging with the Magi among whom he was permitted to dwell. Having enjoyed long experience in the customs of the Magi therefore, he seemed to understand, not obscurely, that Zoroaster the Persian was one of them, as the most ancient of all the philosophers, and thus also the most profound and wisest. Therefore from that time the philosophy of Zoroaster was embraced. Thus afterwards Plato in his turn made use of Pythagoras and was followed by various authors and doctors. They spread, according to what came wisely and acutely from Zoroaster the philosopher himself concerning Idea, writings which are referred to by Plato.

(Filelfo’s Platonic reference to Zoroaster may be referring to First Alcibiades 122a1 :
“And at fourteen years of age he is handed over to the royal schoolmasters, as they are termed: these are four chosen men, reputed to be the best among the Persians of a certain age; and one of them is the wisest, another the justest, a third the most temperate, and a fourth the most valiant. The first instructs him in the magianism of Zoroaster, the son of Oromasus, which is the worship of the Gods, and teaches him also the duties of his royal office; the second, who is the justest, teaches him always to speak the truth; the third, or most temperate, forbids him to allow any pleasure to be lord over him, that he may be accustomed to be a freeman and king indeed,—lord of himself first, and not a slave; the most valiant trains him to be bold and fearless, telling him that if he fears he is to deem himself a slave” (trans. Benjanmin Jowett).

But he doesn't refer to "writings" here, so that's not entirely acceptable. There is another possible intersection of Plato and Zoroaster, when a philosopher named Colotes wrote that Plato had changed the name of Zoroaster to Er in Book X of the Republic. But again, no books are mentoned. Maybe Filelfo's reference is to some apocrypha we don't know about.)
 

MikeH

Thanks for the translation, Ross. A lot better than Google, although I still have questions.

Ross wrote,
Filelfo does believe that the philosophy of "Idea" comes from Zoroaster, but he doesn't cite any writings, just Pythagoras' basis in Magian teachings.

He clearly believes in some kind of "prisca philosophia", but not as Ficino would codify it. There is no mention of Orpheus or the Aglaophemus who was held to be Pythagoras' Orphic teacher.
That Filelfo does not mention Orpheus or Aglaeophemus is not surprising, if his source is Plethon. Plethon doesn't mention them either. That comes from Ficino, already in 1463, when he hadn't added Zoroaster to his list. As for "writings", the crucial sentences are the last two, especially the last:
Thus afterwards Plato in his turn made use of Pythagoras and was followed by various authors and doctors. They spread, according to what came wisely and acutely from Zoroaster the philosopher himself concerning Idea, writings which are referred to by Plato.
It seems like Filelfo means that Plato referred to Zoroaster's writings; but it is a bit unclear (and ultimately I think, relevant but not crucial). In your final comment, aren't you implying that Filelfo is thinking of "writings" by Zoroaster? I assume that by "he" in the first sentence below you mean the author of the Alcibiades, who then was assumed to be Plato. Ross wrote
But he doesn't refer to "writings" here, so that's not entirely acceptable. There is another possible intersection of Plato and Zoroaster, when a philosopher named Colotes wrote that Plato had changed the name of Zoroaster to Er in Book X of the Republic. But again, no books are mentoned. Maybe Filelfo's reference is to some apocrypha we don't know about.)
Another objection to the the Alcibiades as Filelfo's source is that it doesn't refer to the doctrine of the Ideas. It seems to me that in capitalizing the word "Idea" in the last sentence, Filelfo is meaning to attribute Plato's theory of the Ideas, his in particular as it is he who is associated with it, originally to Zoroaster. No one else makes such a radical attribution, that I have found, except Plethon, and Plethon only in the "Brief Description" and the "Commentary" that went with his version of the Chaldean Oracles. I quoted the relevant passages earlier, post 66 (http://www.tarotforum.net/showpost.php?p=2898337&postcount=66). Here are my scans of the pages where Woodhouse gives his translation of the "Brief Description." The relevant part is where, on p. 53, Plethon, in Woodhouse's English, talks about "Forms." "Forms" is just the standard English way of translating Plato's "Ideas" in the technical Platonic sense.

http://4.bp.blogspot.com/-HZ9UJFrGgBE/To4dVmV1ifI/AAAAAAAADk8/z5v3t9uIqWo/s1600/Woodhouse53a.jpg

http://1.bp.blogspot.com/-6E-fPHW8JW0/To4dV52V8BI/AAAAAAAADlE/a3u4gEXkROo/s1600/Woodhouse54.jpg

The Oracles themselves, that the line numbers refer to, I gave at the beginning of

http://www.tarotforum.net/showpost.php?p=2892890&postcount=56

So it seems to me that, given Filelfo's respect for and interest in Plethon's writings, that Filelfo's likeliest source for his last sentence is Plethon's edition of the Oracles, including either the "Brief Description" or the "Commentary" or both.

A difficulty is that these writings by Plethon are probably not among those listed by Calderini in the article that Kwaw cited, the philosophical contents of Filelfo's library. If they were, Hankins would have said so. One possibility is that Filelfo gave them to someone else, when he did not have time to make another copy. It strikes me that Lorenzo's visit to Milan in 1465 might have been such an occasion, a very worthy act of good will toward the Medici, Cosimo's memory, and his protege Ficino, such as might go a long way to repair earlier damage.


Kwaw: thanks for clarifying what the work of Proclus was that was in Filelfo's library, the same work from which the Oracle about the child and the horse comes. It seems to me that with Proclus, Plethon, and Plutarch (or maybe any two of them), Filelfo would have had enough to put together the PMB 2nd artist's Sun card as an apt expression of the planetary daemons of the ancient Zoroastrian-Pythagorean-Platonic philosophy.
 

Huck

800px-Sanzio_01_Zoroaster_Ptolmey.jpg


Detail of "School of Athens" by Raffael
The explanation says:
Zoroaster (= Pietro Bembo, left), Ptolemy (backsight), Raffael (the artist himself as "Apelles", middle), Sodoma (= Michelangelo, right)

It's naturally interesting, that Raffael placed himself beside Zoroaster... but possibly cause he had a personal relationship to Bembo, both are called "friends". From Michelangelo I know, that the Raffael's relation was "competition", they are judged as "unspoken rivals", but this page
http://www.mlahanas.de/Greeks/SchoolAthens.htm
... gives another explanation to this figure.

422px-Raffaello_Sanzio_-_Pietro_Bembo.jpg


Bembo as young man, painted by Raffael (1506)

bembo%20par%20le%20titien.jpg


Bembo as older man.

Perhaps the long beard of Bembo made it attractive to use Bembo's face for Zoroaster.
 

kwaw

Re: Filelfo & Platonic Ideas & Chaldean Oracles : don't know whether this may be of interest : it refers to a letter to Ficino and is probably too late for the present interest : I do not have access to JSTOR and might be worth a follow up to any who have:

http://www.jstor.org/pss/751098

Also, many of the fragments of the oracles Filelfo may also have known through Proclus available to him at the time (not just those in In Remp), e.g. :

http://www.sacred-texts.com/eso/coz/coz04.htm

So in Proclus there are the connections of ancient theology with the oracles/zoroaster - and also 'attic moses' - for example see leo baeck's contention on the influence of Proclus on the Sefer Yetzirah:

http://www.wbenjamin.org/baeck.html#fn55

And while Proclus in his commentaries on Plato gives predominance to the Chaldean Oracles, he also makes references to the mysteries and hymns of Orpheus (Taylor for example references Proclus 24 times in his Mystical Hymns of Orpheus).

A scholiastic note included in Plato's Alcibides also recorded notes on the life of Zoroaster - and in his commentary of Plato's Republic Proclus also reports that sections of the Republic, including for example the myth of Er, were claimed to originate with Zoroaster. So it is possible, depending on what access he had to the works of Proclus, that Filelfo would have found sufficient in proclus alone for himself to trace a 'common theology' akin to (but maybe not quite so formulated as in) the later defined prisca theologia of Ficino or perennial philosophy of Steun - that connected moses, zoroaster, orpheus, plato...

edited to add:

oops - just saw this:

There is another possible intersection of Plato and Zoroaster, when a philosopher named Colotes wrote that Plato had changed the name of Zoroaster to Er in Book X of the Republic. But again, no books are mentoned. Maybe Filelfo's reference is to some apocrypha we don't know about.)

As I note above - Filelfo would have known this from the Proclus commentary on Plato's Republic - (the speculative influence of which on 15th century tarots, in respect of the figuration of the city and the role of the Republic in city-state propaganda and possibly also in reference to the equality of the sexes, we discussed a little in the cary-yale thread).

Clement also describes the myth of Er as being a myth of Zoroaster - for references see here:

http://books.google.com.tr/books?id=6p9ZVm-poRoC&pg=PA188#v=onepage&q&f=false