When Alexander of Macedon marched east, the Samaritans — called in the Talmud the Kutim — saw a political opening. They sent word to Alexander asking him to destroy the Temple in Jerusalem. The Temple, they claimed, was the seat of rebellion. Better to level it before it caused him trouble.
Alexander agreed. He marched toward Jerusalem with the intention of razing the Temple to the ground.
The High Priest, Simeon the Just — the same Simeon celebrated in Pirkei Avot — heard the army approaching. He put on the eight garments of the high priesthood: the breastplate with its twelve stones, the tzitz with the Divine Name on his forehead, the blue robe, the tunic, the belt, the turban, and the priestly undergarments. He took the leading citizens of Jerusalem, and they walked out of the city at night, processing with torches toward the approaching army.
When the two companies met, something strange happened. Alexander dismounted. Alexander bowed. His own generals were stunned. A Macedonian king did not bow to anyone, least of all to a subject priest of a subject city.
Alexander explained: he had seen this man in a dream. Before every major battle of his life, this figure in white robes had appeared to him, leading him to victory. And now the figure stood before him in the flesh.
Alexander spared the Temple. He turned on the Samaritans, delivering them into the hands of the Jews, who destroyed the rival sanctuary on Mount Gerizim. The anniversary of that day was declared a festival.
Gaster's Exempla (no. 279, 1924) preserves this story because it insists that even the conqueror of the world was, without knowing it, guided by a Jerusalem dream. No emperor conquers alone.