Complex sentence: Mir Murad Buksh Khan Mazari had earlier succeeded his elder brother Mir Dost Muhammad Khan Mazari as the Chief and they were the sons of Mir Sher Muhammad Khan Mazari, the Ninteenth Sardar and Fourth Mir of Mazaris.
Split into simpler sentences: Mir Murad Buksh Khan Mazari had earlier succeeded his elder brother Mir Dost Muhammad Khan Mazari as the Chief. They were the sons of Mir Sher Muhammad Khan Mazari, the Ninteenth Sardar and Fourth Mir of Mazaris.