How large was William I’s invasion army in 1066?

When William I, Duke of Normandy, launched his invasion of England in 1066, he led a diverse force composed of cavalry and infantry recruited from Normandy, Brittany, Maine, France, Flanders, Spain, and Italy.1

Historical estimates place the size of William’s invasion army at between 4,000 and 7,000 men. Successfully organizing the supplies, transport, and disciplined cohesion of this miscellaneous host is considered one of William's greatest military achievements.12