(lay name, Roman). Died after 1398 in Moscow. Participant in the battle of Kulikovo of 1380. Monk of the St. Sergius Trinity Monastery. Boyar before he was tonsured.
Along with Peresvet, Osliabia accompanied Grand Prince Dmitrii Ivanovich Donskoi to the battle of Kulikovo. In 1398 he traveled to Constantinople with an embassy sent by Grand Prince of Moscow Vasilii to assist the Byzantine Empire, which was then suffering devastating Turkish raids.