Ernst von Mansfeld was a German military commander in the Thirty Years War. Although he fought for the Protestant cause, Mansfeld was a Roman Catholic. He was considered one of the most dangerous opponent of the Catholic League. He was born in 1580 as the illegitimate son of Peter Ernst I von Mansfeld-Vorderort and Dorothea von Solms- Lich. In 1594 he served under Archduke Leopold. Then, in 1610 he joined Frederick V and the Protestant Union. At the age 36 he led his first regiment of 2000 men. He fought for the Protestant Union until he died from illness in November, 1626.
In the Bohemian Phase of the Thirty Years’ War Mansfeld led an army of 2000 men, raised by the Duke of Savoy, to aid the Bohemian rebels. He successfully siege the Bohemian city of Pilsen in 1618. Mansfeld was defeated in the Battle of Sablat after being inactive for a while. At the Battle of White Mountain Masfeld and his forces were defeated, and in shortly after forced to surrender Pilsen to the Catholics.
Toward the end of the Bohemian Phase King Frederick V selected Mansfeld to lead his Bohemian troops. Following this he undertook Frederick’s position in Upper Palatinate. He then moved into Rhenish Palatinate. This allowed Mansfeld to successfully defend against Johann Tserclaes, the Count of Tilly’s attempt at overtaking Bohemian rebel regiments. He also was defeated by Tilly twice. Mansfeld’s troops were very destructive, not only to the lands of his enemy, but to the lands he was supposed to defend.
During the Palatine Phase of the Thirty Years’ War Mansfeld raised another of Frederick V’s armies in an effort to recover Palastine. The effort was a failure, because he was once again defeated by Tilly. Then Mansfeld was given an army of 12,000 men by James I of England. These troops were sent into the Dutch city of Breda as an attempt of relief for the Siege of Breda, but the troops were not permitted set foot on land, and Breda fell in 1625.
Mansfeld led the remainder of his army to Dutch lands, where they were once again defeated by Habsburg forces. Mansfeld continued to fight. He led his forces to Bergen-op-Zoom, a Dutch city seiged by the Spainish in 1622. This led to the relief of the city.
Mansfeld spent 1624 and 1625 raising an anti-Habsburg army. He led this coalition in a march on Bohemia in 1626, but in a turn of events Mansfeld was forced to turn to Hungary. He intended on returning to his base after being defeated by Tilly once again. On his return home Mansfeld fell ill, and on November 29, 1626 he died in Bosnia.
Mansfeld was a great force to be reckoned with during Thirty year’s War. The Protestant Union can contribute much of their success during the early phases of the war. He was remarkable because he fought for the Protestant cause while remaining a faithful Catholic.