According to these texts, Alexander had what we today would consider a "body double" or "look a like"- impersonate him on the throne of Babylon beginning in the spring of 323 B.C. A prophecy had frightened Alexander about an early decline and demise, and Alexander did not trust some of the generals and advisors that surrounded him, even suspecting that one might attempt to move on his life. He found a young Macedonian soldier who many had claimed had an eerie resemblance to himself- and secretly trained him in the ways and manners of the Macedonian/Babylonian court. This impostor took the throne as Alexander- with Alexander's approval and Alexander, temporarily went into hiding- until the time of the prophecy could pass.
When disaster struck as the prophecy had indicated and the impostor got very ill with fever, it was too late for the real Alexander to come forward and reveal the ploy. The impostor did not know what to do when pressed for who would be Alexander's heir- since he wasn't actually Alexander- and Alexander's empire immediately split into chaos as different generals took their piece of his kingdom.
The real Alexander lived out the rest of his days quietly in the Seleucid kingdom, and it is debated by Chaldean historians whether he married other women and had children.
Source: The Sepher Yetzirah. Translated by Michael Crolier.
