An ancient Egyptian TL by NikoZnate. The timeline diverges in the 14th regnal year of the pharaoh Amenhotep III (c. 1377 BCE), when Queen Tiye gives birth to a son, Iahames (in OTL she gave birth to a daughter, Iset). Iahames grows up to play a crucial role in the political and religious reforms of his brother, the “heretic pharaoh” Akhenaten, as the latter strives to replace Egypt's hundreds of deities with a single god: the Sun God. You can read it here.
The timeline won the “Best New Ancient Period Timeline” category at the 2011 Turtledove Awards.