He was born in Prague as son of the hapless 'Winter' King and Queen of Bohemia. Educated at the University of Leiden in The Netherlands, he also entered the army at the age of thirteen. In 1636 
he accompanied Karl Ludwig, his elder brother, on a short visit to the English Court. A year later he joined with the same brother a small Dutch army which went to Germany to support the Swedes against Imperial forces. However, they were cut off by the Imperial army. Karl Ludwig managed to escape but Rupert was captured and kept a prisoner at Linz in Austria for three years. 
After his release he went to England and was naturalised on 19 January 1642. In the same year he became General of the Horse and on 24 January 1644 his uncle, King Charles I of England, created him Earl of Holderness and Duke of Cumberland. He was Commander-in-Chief of the Royal army in 1644 and 1645 and played an important role in the struggles with Parliament and Oliver Cromwell. 
In 1650 he was banished by Parliament and led the small Royalist fleet until it was routed by Blake. He escaped to the West Indies  but returned to Europe in 1653, and lived in Germany until the 
Restoration. 
He was Master of the Horse to Charles II in exile from 1653 till 1655 and was sent as his envoy to Vienna in June 1654. After the restoration of Charles II he returned to England and, as Admiral of 
the White, served under the Duke of York in the crushing defeat of the Dutch off Lowestoft on 3 June 1665. 
In 1668 he became Constable of Windsor Castle and in 1672 Vice-Admiral of England. He died unmarried but had fathered two illegitimate children, a son by Frances Bard and a daughter by the 
celebrated actress, Mrs. Margaret Hughes.
 

Source: Leo van de Pas