Afterwards, Alexander travelled to Ecbatana to retrieve the bulk of the Persian treasure. There, his closest friend and possible lover, Hephaestion, died of illness or poisoning. Hephaestion's death devastated Alexander, and he ordered the preparation of an expensive funeral pyre in Babylon, as well as a decree for public mourning. Back in Babylon, Alexander planned a series of new campaigns, beginning with an invasion of Arabia, but he would not have a chance to realize them, as he died shortly after Hephaestion.