The Ghaznavids were a Persianate Muslim dynasty of Turkic slave origin which existed from 975 to 1187 and ruled much of Persia, Transoxania, and the northern parts of the Indian subcontinent. The Ghaznavid state was centered in Ghazni, a city in modern-day Afghanistan. Due to the political and cultural influence of their predecessors - that of the Persian Samanid Empire - the originally Turkic Ghaznavids had become thoroughly Persianized. The dynasty was founded by Sebuktigin upon his succession to rule of territories centered around the city of Ghazni from his father-in-law, Alp Tigin, a break-away ex-general of the Samanid sultans. Sebuktigin's son, Shah Mahmud, expanded the empire in the region that stretched from the Oxus river to the Indus Valley and the Indian Ocean; and in the west it reached Rey and Hamadan.