He was the son of Philip, Duke of Burgundy, by Joanna, daughter
of Ferdinand and Isabella. He succeeded his father in 1506 as
Charles I, King of Spain, and was declared the successor of
Ferdinand of Aragon in 1516. In 1520 he was elected Holy Roman
Emperor in the face of the opposition of Rome and France. At the
Diet of Worms in 1521, he appealed in person against Luther. In
1522 he gave his Austrian possessions to his brother Ferdinand
and established a permanent regency for the Netherlands. From
1521 to 1529 he waged war against Francis I, whom he defeated at
Pavia, Italy in 1525, and after the French coalition with Pope
Clement VII, marched against Rome, which was sacked by
undisciplined troops in 1521. The Peace of Cambrai (1529)
concluded the struggle. Charles established legislation which
regulated the social and industrial life of the Netherlands,
adopted a progressive policy in Spain, and dealt successfully
with colonial politics in America. He received the imperial
crown from Clement VII, at Bologna