The penultimate Russo-Byzantine War, as documented by medieval Greek sources, took place in 1024, when a relative of the Kievan prince with 800 men and 20 ships penetrated into the Bosporus and, defeating a unit of the Greek coast guard, sailed into the Aegean Sea. The Kievans reached the island of Lemnos, where they were annihilated by a much stronger Byzantine fleet. The conflict is not documented in Kievan sources and its motivation is obscure.