Michael IV (Μιχαὴλ) was a Byzantine and Eastern Roman emperor of the 11th century. He became emperor merely due to his relationship with Zoe Porphyrogenniti but grew to distrust her. His military exploits were mixed with the Arabs, Serbs, and Pechenegs, but had a decisive victory against the Bulgarians on one occasion. His reforms to the army and financial system were beneficial but were not popular.