Sicco van Goslinga Sicco van Goslinga ( Herbaijum , Friesland , 1664 — Dongjum , September 20 , 1731 ) was a Dutch statesman and diplomat , who served as " gedeputeerde te velde " ( deputy - in - the - field , a kind of political commissar ) of the States - General of the Dutch Republic with John Churchill , 1st Duke of Marlborough during his campaigns in Flanders in the War of the Spanish Succession . His memoirs form an important source of information for historians of the period . Biography . Family Life . Goslinga married Jeanette ( Joanne ) Isabelle baroness thoe Schwartzenberg und Hohenlansberg , vrijvrouwe of Ameland , at Ballum , Friesland , on June 12 , 1692 . They had five daughters one of whom , Anna Dodonea , would marry Unico Wilhelm van Wassenaer . Career . After studies at the University of Franeker and the University of Utrecht he became " Grietman " of Franekeradeel in 1688 , a function he would hold until his death . This made him a regent and put him in line for all kinds of functions on a provincial level in the province of Friesland . He also represented that province in the States - General and in the " Raad van State " ( Council of State ) on many occasions ( see " List of functions " in the External Links ) . As a member of the Council of State ( which was the most important executive organ of the Republic in the military field , especially after the Second Stadtholderless Period had started ) he became a " gedeputeerde te velde " for Friesland at the headquarters of the Duke of Marlborough from 1706 until the Duke ' s dismissal in 1711 . As such he was charged with advising the Duke , and with keeping an eye on him , as agreed when Marlborough was made lieutenant - captain - general of the army of the Republic in 1702 . The Dutch deputies - in - the - field had the right to veto the Duke ' s tactical decisions if they thought the interests of the Republic demanded it , and this had led to much friction with Marlborough in previous years . Goslinga , however , proved cooperative generally and managed to provide a positive contribution during the battles of Ramillies , Oudenaarde , and Malplaquet . Though not a general , he was authorized to give orders to Dutch commanders at these battles . At the Battle of Oudenaarde he took it upon himself to throw a Dutch division into battle at a decisive moment . Another incident had him personally ordering up reinforcements at the battle of Malplaquet , when the second Dutch assault on the left flank faltered . To illustrate the good rapport between the Duke and Goslinga , Churchill mentions the anecdote in which they shared the Duke ' s cloak to sleep on after the battle of Ramillies . Though Churchill has no high opinion of Goslinga ' s military abilities he nevertheless extensively used his memoirs as a source . Goslinga served as plenipotentiary for the Republic at the peace negotiations , leading up to the Treaty of Utrecht ( 1713 ) . After the conclusion of the peace he served as extraordinary envoy of the Republic to the court of Louis XIV of France in 1714 and 1715 . In 1728 he represented the Republic at the congress of Soissons about outstanding European diplomatic issues ( like the status of Gibraltar ) . Until his death he was involved in Dutch politics . He supported the appointment of William IV , Prince of Orange as stadtholder of Groningen in 1719 .