On Runes.
Huge question.
On one level it is a system of idiographic writing (communication).
On another level, it is a system of communication with the Gods, a system for reading that which is hidden from our humanistic view. They are cosmic tools.
They work as part Oracle, part divination system.
As a writing system, it dates to around 200 BCE, and was used in various forms with the Teutonic and the Norse tribes.