Why was tostig in exile?

Tostig Godwinson, the Earl of Northumbria, was in exile primarily due to his unpopularity with the Northumbrian nobility and his harsh rule. His attempts to impose heavy taxation and favoritism toward southern interests alienated local leaders, leading to a rebellion that resulted in his ousting in 1065. After his exile, Tostig sought support from King Harold Godwinson and later allied with the Norman Duke William, ultimately playing a significant role in the events leading up to the Norman Conquest of England.