Walter Leslie ( 1607 – 1667 ) Walter Leslie ( Fetternear House , Aberdeenshire , 1606 – Vienna , 4 March 1667 ) was a Scottish Soldier and diplomat . He gained the positions of Imperial Field Marshal , Count of the Holy Roman Empire , Governor on the Croatian - Slavonian Military Frontier , Imperial Ambassador to Naples , Rome in 1645 and to Constantinople in 1665 - 1666 . Family . Walter Leslie was born to a prominent Scottish noble family from the Clan Leslie . His father William was the 10th Baron of Balquhain and his mother Joan was a daughter of John Baron of Gogar . In 1647 , he married Anna Francesca von Dietrichstein , daughter of Count Maximilian von Dietrichstein . They had no children . He was succeeded by his nephew , Count James Leslie , who continued the Leslie line at the family castle , Nové Město nad Metují . Early Military Career : 1624 - 1632 . In 1624 , Walter Leslie crossed the North Sea to fight with the Protestant Army of the United Provinces . By 1628 , he was in Stralsund in Northern Germany fighting for either the Danes or the Swedes . In 1630 , he transferred to the Imperial Army and fought alongside his countryman John Gordon that summer in War of the Mantuan Succession in Northern Italy , under the command of General Albrecht von Wallenstein . Wallenstein was recalled from Italy in 1631 . In December of 1631 , Leslie followed the General to fight in Northern Germany against the Swedes . By July of 1632 , Leslie had risen to the rank of oberwatchmeister , or sergeant in the infantry ranks of Count Adam Erdmann Trčka , Wallenstein ' s brother - in - law , and was still under John Gordon , then Lieutenant Colonel . The military relationship between Leslie and Gordon would become increasingly important as they became closer to Wallenstein . Leslie fought under Gordon at Bentheim in lower Saxony and at Freistadt in upper Austria . Both men were captured at Freistadt by the Swedes after having had joint command of 1000 Scottish and Irish musketeers . After that , Gordon rose to commander of a regiment and Leslie became his spokesman in court . This was the first time Leslie was put in such a position , although it would not be the last . In November of 1632 , Leslie fought with Gordon at the Battle of Lützen . That was a Protestant victory , but cost the life of Gustavus Adolphus of Sweden . After that , they captured Eger and Leslie was again commissioned as Gordon ' s second in command . The Assassination of Wallenstein : From Plot to Execution , 1633 - 1634 . In December of 1633 , Italian Imperial generals began to plot ways to remove Wallenstein from power . During that time , Leslie , Gordon and Irish Colonel Walter Butler remained in the service of Wallenstein but began to correspond with the Italian generals . Leslie wrote to one , calling him the " protector of all foreign cavaleirs , " pledged his allegiance to the Ferdinand II and requested a promotion based on his service to the emperor . As historian David Worthington points out , the letter was timed to arrive on January 12 , the day before the Pilsen Agreement was signed by 47 of Wallenstein ' s officers to remain loyal to him . Leslie never signed the agreement . Days later , the Italian generals and 18 other senior officers signed the Pilsen Reverse , a document which expressed their loss of faith in Wallenstein ' s loyalty and ability . In January of 1633 , Ferdinand II granted immunity to all signers of the Pilsen Agreement except the top generals . By this time , Leslie and Gordon had both aligned themselves with one of the Italian Generals who had just been made a Field Marshall and had been preparing their musketeers in Eger . In January of 1634 , Ferdinand issued a secret arrest warrant for Wallenstein . The General began exploring the allegiances of his Scottish officers , Gordon and Leslie by offering Gordon a promotion and asking to meet with Leslie . As Butler escorted Wallenstein into Eger , Leslie and Gordon were inside the castle walls awaiting their arrival . There are several accounts of what followed in the late days of February , but some events and details are unanimous . On February 24 , Wallenstein entered Eger and retired to his bed at the Burgomaster ' s house , outside the castle walls . That night , Leslie dined with Butler and Gordon and they finalized their plans to assassinate Wallensteina and his senior officers . After dinner , a messenger came for Wallenstein and Leslie took him to the general ' s quarters . The letter was from Ferdinand II and it officially dismissed him as a general and indicted him as a traitor . Wallenstein is then reported to have let out his frustrations to Leslie and even confided in Leslie his plans to join forces with Saxe - Weimar . The next morning , Leslie , Butler and Gordon all took an oath with one of the loyalist officers , Ilow , to remain loyal to Wallenstein . Later that day , the Scotsmen invited all of the loyalist officers to a banquet to celebrate Wallenstein . Adam Trčka , Vilem Kinsky , Christian Ilow and a lower ranking officer , Niemann all attended , but Wallenstein declined due to illness . At the banquet they drank heavily , made toasts to the General , cursed the court in Vienna and had dessert . Again , reports of events differ slightly in the small details but what is agreed is that at the end of dinner , Leslie , Butler and Gordon all stood up , drew their swords and yelled something along the lines of " Long live Ferdinand and the House of Austria ! " At that point , the drawbridge had been raised and the Irish dragoons had been let into the banquet hall . Although Leslie was wounded in the slaughter , all of Wallenstein ' s officers were killed . Next , Leslie left the walls to gather Walter Devereux and a team to go to Wallenstein ' s quarters , where he was asleep , and kill him , and so they did . Leslie was the first to bring word to Vienna and therefore the Emperor heard his name first . Leslie and his fellows were rewarded handsomely by Ferdinand II for their efforts . Leslie was given Trčka ' s castle , Nové Město nad Metují and some other properties as well as the " die golden ketten " or the imperial golden chain . Leslie ' s career as a military officer , politician , diplomat , and imperial noble skyrocketed as a result of assassinating Wallenstein . The Imperial Court , New Titles , and Diplomacy : 1634 - 1650 . Leslie was made an Imperial Chamberlain by Ferdinand II in 1634 . His military rank was increased to a Lieutenant Field Marshall and Head of the Bodyguard for the King of Hungary and he was given command of two regiments . Just after his promotions , in the summer of 1634 he led a successful siege on Regensburg . In September of 1634 , he fought at the imperial victory at the Battle of Nordlingen . In the months leading up to the Peace of Prague , Leslie was in Rathenow in Brandenburg . Historian David Worthington claims that of all the assassins of Wallenstein , Leslie was rewarded the most and ultimately his career grew the most out of that event . In September of 1636 , Leslie and the imperialists were defeated by the French , the Swedes and Saxe - Weimar at the Battle of Wittstock . However , in 1637 , Leslie wrote to the dying Ferdinand II , making his argument that he had Hapsburg blood dating back over half of a century . After Ferdinand II ' s death , Ferdinand III approved the request and ennobled Leslie as an Imperial Count . This new title brought with it a new lifestyle , new political respect and more diplomatic opportunities . Leslie served as a Stuart - Hapsburg intermediary at the Ratisbon Electoral meeting ( 1636 – 43 ) , Imperial envoy to the Spanish Netherlands ( 1639 ) , diplomatic trips to the Caroline Court in Spain , delegate in Regensburg ( 1640 ) , and ambassador to Naples in 1645 . In 1645 , Leslie , then Imperial Ambassador to Naples , roamed the Italian Peninsula in an attempt to garner funds to fight the war . He is reported to have given Pope Innocent X a solid silver writing table . The trip yielded little money and few troops . Latter Years , Ottoman Diplomacy , and Death : 1650 - 1667 . Leslie was made a Field Marshal and the Governor of the Croatian - Slavonian Military Frontier in 1650 , an appointment that drew his attention to the Southern reaches of the Holy Roman Empire . During this period , there is evidence that his lifestyle became more relaxed . In the 1650s , Leslie renovated his castles , Nové Město nad Metují and Ptuj . He also continued a passion of his , collecting and commissioning works of art , especially portraits . He commissioned portraits for Ferdinand II , Ferdinand III , Leopold I and most of their families . In 1657 , he was made Vice - President of the Imperial War Council . He had been an adviser to the Imperial Privy Council for some years . In 1663 , he willed his estates and titles to his nephew , James Leslie . In 1665 , Walter was made a Knight in the Order of the Golden Fleece . Shortly after that , he embarked on his last diplomatic journey as Imperial Ambassador to Constantinople , a trip that lasted from 1665 until 1666 . In Istanbul , he moved along peace treaty talks with Sultan Mehmed IV . Upon his return in 1666 , Leslie ' s health was failing . He died on March 3 , 1667 and was buried in the Scottish Benedictine Abbey in Vienna . Leslie had commissioned the renovation of this very same church years earlier .