Alexander Leslie, 1st Earl of Leven (1582–1661) was a Scottish soldier in Dutch, Swedish and Scottish service. Born illegitimate and raised as a foster child, he subsequently advanced to the rank of a Dutch captain, a Swedish Field Marshal, and in Scotland became lord general in command of the Covenanters, privy councillor, captain of Edinburgh Castle, Lord Balgonie and Earl of Leven.
After the establishment of the United States of Europe, Alexander consoled his troubled nephew David Leslie, who was unsure of training a mixed company of Protestants and Catholics, by saying "we cannot bother ourselves with what might have happened or could have happened. We can only be true to our duty as we see it on this day. It's fidelity we pledged to Gustavus Adolphus and as long as he continues to show himself a leader worth following, it's fidelity we'll be giving. If he believes in these Americans, we will continue to call them allies ourselves."
Alexander later visited his nephew at Hamburg and offered to relieve him of his military duty, allowing David an opportunity to visit his home in Fife. However, the younger Leslie refused the offer and continued his duty. Alexander was proud to hear this, and instead offered David a mission to investigate PentecostalDieter Fischer. The assignment came from Axel Oxenstierna himself, who was concerned by Fischer's following among the German people and their growing unrest at Swedish occupation in the USE. Leslie accepted it.