It was powerful and had the ability to create. To the Egyptians, writing was a gift of the gods and should be used accordingly. He is more commonly known as the scribe who records judgment in the famous weighing of the heart scene in which a person's fate in the afterlife is decided Thoth was originally a lunar god, strongly associated with recording events and time.
He was a scribe, also associated with mathematics, medicine, and astronomy, and could appear as either an ibis or a baboon. Even the ancient Egyptians saw their writing systems as full of mystery and hidden knowledge - according to Egyptian mythology, writing was invented by the ibis-headed god Thoth, the most intellectual of the gods. Perhaps not surprisingly given how advanced they were in comparison to contemporaries, the Egyptians invented one of the first writing systems ever, and for centuries, people thought these ancient texts held some sort of secret, be it aliens, advanced technology lost to the world, or mystical cures for all of the world's ills.
*Includes a bibliography for further reading
