In the civil war of 1642-45, the cavaliers fought on the side of
the roundheads
oliver cromwell
charles i
the puritans

Charles I

Explanation:

The term "Cavalier" was first used in a derogatory way by the Roundheads in order to describe wealthy Royalists supporters. The Cavaliers supported King Charles I and his son Charles II of England. Cavaliers were a significant part of the English political life during the English Civil War, the Interregnum period and the Restoration. Eventually, the term was adopted by the Royalists themselves. Nowadays, the term is often associated with the style of dress of the court at the time.

c, to compete

a widespread disease that killed many people

the split of the christian church

invasion from arab muslims