Ghiyath al-Din Muhammad (Persian: غیاث‌ الدین محمد بن سام‎), was sultan of the Ghurid dynasty from 1163 to 1202. During his reign, the Ghurid dynasty became a world power, which stretched from Gorgan to Bengal. During his early reign, he defeated the Ghurid claimants to the throne and fought with the Khwarazmian Empire over the lordship of Khorasan. He occupied Herat in 1176 and went on to establish control over most of what is now Afghanistan and the surrounding areas by 1200, and as far west as Bastam and Gurgan. His brother, Mu'izz al-Din, helped manage and expand the eastern part of the empire (as far as Bengal) and served Ghiyath with utmost loyalty and deference. Ghiyath died in 1202 and was succeeded by his brother Mu'izz al-Din.