Complex sentence: Because of the Ottoman advance, he burnt his house and settled in Drenica, in Kosovo, and participated in the Battle of Kosovo (1389), of which outcome was inconclusive, though a long-term strategic victory for the Ottomans.
Split into simpler sentences: Because of the Ottoman advance, he burnt his house and settled in Drenica, in Kosovo. He participated in the Battle of Kosovo (1389), of which outcome was inconclusive, but a long-term strategic victory for the Ottomans.