Board Thread:Lore Discussion/@comment-9062114-20131115185253/@comment-1600847-20131118175145

If you read the Elder Scrolls novels The Infernal City and Lord of Souls, it's shown by the Oblivion- Hists to Mere-Glim that the Argonians used to be normal lizards like crocodiles or monitor lizards, then they were changed by the Tamriel-Hists until they became the Argonians we know and love today.

Who created the non-sentient lizards they were before the Hists mutated them is still unknown.