Alexander the Great began his conquest of Persia in 334 BC.

Evidence

Alexander the Great’s conquest of the Persian Empire in 334 BC ushered in an age of megalomaniac rulers and great empires. — Neil MacGregor, A History of the World in 100 Objects, 511

Categorization

• corroborated: 2 independent passages support this claim — Neil MacGregor, A History of the World in 100 Objects, 511