Complex sentence: Mahmud of Ghazni was the crowned ruler of this empire though it was founded by Sebuktigin.Sebuktigin`s son Mahmud, expanded the empire that stretched from the Oxus River to the Indus Valley and the Indian Ocean and in the West too.
Split into simpler sentences: Mahmud of Ghazni was the crowned ruler of this empire though it was founded by Sebuktigin. Sebuktigin's son Mahmud, expanded the empire that stretched from the Oxus River to the Indus Valley and the Indian Ocean and in the West too.