The 30 Years' War began as a struggle between German Protestant princes & this Catholic "Empire"
... one of the few Calvinist princes in the Holy Roman empire, Frederick V 
of the... [DOC] [TLE] The Thirty Years' War (1618-1648) - Femling [PAR] The Thirty Years' War has been described as the last major European war of ... of 
wars, fought mainly on German soil, and was in large part a struggle to alter the ... 
a peace between the Protestant and Roman Catholic states of the empire that ...