Alexander V. Maiorov. "A medieval effort toward unity: Latins, Greeks, Russians and the Mongol Khan." Journal of Medieval History, volume 39, issue 4 (2023): pp. 499–515.

This article explores the little studied role of the Rus princes and the Rus prelates of the Byzantine Church in the establishment of immediate contacts between the papal court and the rulers of the Nicene Empire in the mid thirteenth century. These resulted in a new round of negotiations for the union of the Roman Church and the Byzantine Church. At the heart of these contacts was not only the mutual desire of the Latins and Greeks to restore church unity, but also the action of a third force, namely the political ambitions of the Mongol khan toward Christian rulers of the West and, above all, the pope. These rulers took the initiative to turn to him with a proposal for peace in the aftermath of the devastating Mongol invasion that reached Central Europe in 1241–2.