Wilhelm von Knyphausen Wilhelm , Reichsfreiherr zu Innhausen und Knyphausen ( 4 November 1716 Lütetsburg ( ( Ostfriesland ) ) – 7 December 1800 Kassel ) was a general from Hesse - Cassel . He fought in the American Revolutionary War , during which he led Hessian mercenaries on behalf of the British Empire . Biography . His father was colonel in a German regiment under the Duke of Marlborough . Knyphausen was educated in Berlin , entered the Prussia n military service in 1734 , and in 1775 became a general officer in the army of Frederick the Great . In the army of Hesse - Kassel ( or Hesse - Cassel ) , Knyphausen was a lieutenant general . In 1776 , with 42 years of military experience , he came to the Thirteen Colonies of North America as second in command of an army of 12 , 000 so - called “ Hessians ” under General von Heister . Knyphausen led the Hessian troops in the Battles of White Plains , Fort Washington , Brandywine , Germantown , Springfield , and Monmouth . In 1779 and 1780 , he commanded British - held New York City . When Heister left for Germany , von Knyphausen took command of the German troops serving under Sir William Howe . Because of von Knyphausen ' s seniority , ranking British officers held dormant commission s outranking him in case the British commander became disabled . Despite this , von Knyphausen was trusted by his British superiors . Von Knyphausen ' s regiment took part in the attack on Fort Washington and was in garrison at Trenton , New Jersey . Major von Dechow , who was in command in late 1776 , warned Colonel Johann Rall to fortify the town , advice that was ignored . During the Battle of Trenton the regiment tried to escape across Assunpink Creek but was forced to surrender . Major von Dechow was mortally wounded during the battle . Sir William Howe gave von Knyphausen responsibility for the right flank at the Brandywine , tasked with keeping the attention of the Continental commanders on the river line at Chadds Ford , Pennsylvania . He also commanded the vanguard of the army withdrawing from Philadelphia at the time of the Battle of Monmouth . For several years the main body of his soldiery occupied the upper part of Manhattan Island , and during the temporary absence of Sir Henry Clinton , in 1780 , he was in command of the city . Von Knyphausen ' s regiment served in the Americas from 1776 to 1783 . Knyphausen left the North American theater in 1782 in part because of ill health , including blindness in one eye caused by a cataract . ( His wife had died in 1778 . ) Friedrich Wilhelm von Lossberg succeeded to command of the Hessian troops in New York . Von Knyphausen returned to Europe , having , as he said , achieved neither glory nor advancement . At the end of his life Knyphausen became military governor of Cassel . He was a taciturn and discreet officer , who understood the temper of his troops , and rarely entered on hazardous exploits . His was a hireling army of recruits gathered from work - houses , and by impressment , and drilled in the use of arms on shipboard . As he frequently declared , on such forces a judicious commander could place little reliance ; they dwindled less by death than by desertion . In 1785 , shortly after the war , General Lafayette travelled to Kassel and met Knyphausen . He wrote to General Washington that they reminisced about the war and exchanged compliments .