Complex sentence: Al-Baqir had a prominent lineage, His paternal and maternal grandfathers, Hasan ibn Ali and Husayn ibn Ali, were Muhammad's grandsons and his mother, Fatima Umm Abd Allah, was a daughter of al-Hasan (the son of Ali).
Split into simpler sentences: Al-Baqir had a prominent lineage, his paternal and maternal grandfathers, Husayn ibn Ali (and (Hasan ibn Ali)), were Muhammad's grandsons. His mother, Fatima Umm Abd Allah, was a daughter of al-Hasan (the son of Ali).