Sir Walter Leslie was a 14th-century Scottish nobleman and crusader. Along with his brother Norman Leslie, he participated in a 1356 reysa against the Prussians. He had returned by 1356. On 25 November 1363, King David II of Scotland obtained from King Edward III of England a safe-conduct for Walter and Norman to travel to the Holy Land. They traveled via Italy; they appear as witnesses to a deal signed by the authorities of Florence with the notorious English "White Band", a group of English mercenaries who had fought in the Hundred Years War plying their trade in Italy. Walter and Norman eventually joined the crusade of King Peter I of Cyprus, as the latter attacked the Egyptian city of Alexandria. The city was captured, but King Peter was unable to hold it, and abandoned the city after looting it.
Walter returned to Scotland in 1366, and was warmly welcomed back by King David. The king was fascinated by the cult of the crusader, and Walter's previous exploits had already made him one of the royal favorites. As a reward for his latest adventures, King David married him to Euphemia, daughter and heiress to Uilleam III, Earl of Ross, who was bullied by David into allowing the marriage. The marriage took place on 13 September the same year. When King David died in 1371, Walter may have been worried that the new king, Robert Stewart, who was an ally of Earl Uilleam's, may have rescinded the patronage. However, the new king did not, and when Earl Uilleam died in 1372, his wife inherited the title, and he became Lord of Ross.
Walter died at Perth on 27 February 1382. He left two children, Alexander (the future Earl of Ross) and Mariota, who would marry Domhnall, Lord of the Isles. Although Alexander did eventually inherit the Earldom, after Walter's death, de facto control of the Ross passed temporarily into the hands of Alexander Stewart, Lord of Badenoch, who married Countess Euphemia.
- Boardman, Stephen, The Early Stewart Kings: Robert II and Robert III, 1371-1406, (Edinburgh, 1996)
- MacQuarrie, Alan, Scotland and the Crusades, 1095-1560, (Edinburgh, 1997)
- thePeerage.com (retrieved 26 July 2006)