Murray's earliest research was on the composition of the
First Crusade (1096–1099) and the early history of the
Frankish principalities of
Outremer, and was especially informed by prosopographical and pragmatic approaches. He later became interested in the history of the Baltic region, and edited three collections of essays bringing together work by historians in Estonia, Latvia, Denmark, Sweden, Finland, Germany, Russia, the United Kingdom, the U.S.A., and Canada. In 2011, he received the Vilis Vitols Award, bestowed annually by the Association for the Advancement of Baltic Studies for the best article published in the
Journal of Baltic Studies. His biography of
Baldwin of Bourcq, count of Edessa and king of Jerusalem (published 2022), won the J. F. Verbruggen Prize, awarded by De Re Militari: The Society for Medieval Military History "for the best book on medieval military history published within the prior three years". He writes in English and German; several of his publications have also been translated into Estonian, Dutch, Slovene, Spanish and Turkish. ==Major works==