http://www.tarotpedia.com/wiki/Sermones_de_Ludo_Cum_Aliis
this is the first mention of tarots (c.1470)
I guess this sermon addressed tarots and not other card games because they probably were more popular as a gambling game?
The noted link has the information:
"c.1470 is probably the earliest plausible date. (Steele dated it from 1450 to 1480.)"
This is not a fact, this is an opinion. The noted fact is, what Ron Decker wrote (also at the page): "The manuscript pages have many different watermarks. All of them date from around 1500 and come from places near Ferrara. The order of the Tarot trumps, as given in the manuscript, is the Ferrarese order. The author was definitely a monk. One of the sermons is about the stigmata of St. Francis, so I think it likely that the monk was a Franciscan. I do not know on what basis others have declared the author to have been a Dominican."
Naturally the text could have been written earlier. Indeed there is a research of Thierry Depaulis, which found, that a specific other text appearing possibly around 1470 had similarity to the later text, but inside this text the attack at Trionfi cards was missing. So the conclusion is, that the earlier text had been updated and changed in a later process.
The later text is unusual in this "attack on Trionfi cards", usually Trionfi cards during 15th century were "allowed", even when other card games were prohibited.
A form of persecution of Trionfi cards might have happened in the time of Savonarola's regiment (1494-98) and possibly still a little later.
Decker points to Franciscans near Ferrara (Ferrarese order, Franciscan themes in the codex). From the current duke of Ferrara, Ercole d'Este (1471-1505) it is known, that he had an orientation towards Savonarola (he hoped, that Savonarola would become a Ferrarese saint) and that he turned religious at the end of his life. After Savonarola was burnt, he collected nuns with stigmata in the hope, that these become saints. Member of the Savonarolists still had a refugium at Ferrarese territory after Savoarola' death. This might be well the time, when the paper was written. Ferrara had then (as an exception) a playing card prohibition and inside the longer 15th century and later Ferrara had been usually a producer state for Trionfi cards and not a state against playing cards.
this is the first mention of tarots (c.1470)
This is NOT the first mention of "Tarots". The first notes of expressions similar to Tarot appears, as I've written to you in the other thread ...
http://tarotforum.net/showthread.php?p=2930980&highlight=Chiama+fante+venea#post2930980
... (mid of the 1490's for "Taroch" without relation to playing cards; and 1505 with relation to playing cards).
A general expression for cards similar to the later Tarot had been ludus triumphorum, Trionfi, Triumphi, Triunfi etc. and these notes appear for the first time in February 1442 in Ferrara.
We've collected them (the list is not totally complete in the moment; you have to use the menu left):
http://trionfi.com/0/e/01
It is not clear, that all these notes relate to types of decks totally similar to the later Tarot. For instance there is a strong debate about the number of trumps in the early variants. Also there are variants of the motifs.