Complex sentence: Sake Dean Mahomed also mentions how Mir Qasim and most of the entire Bengali Muslim aristocracy had lost their famed wealth and complained regarding Shuja-ud-Daula and his campaign against his Rohilla allies and how Hyder Ali defeated the British during the Battle of Pollilur.
Split into simpler sentences: Sake Dean Mahomed also mentions how Mir Qasim and most of the entire Bengali Muslim aristocracy had lost their famed wealth. He complained about Shuja-ud-Daula's campaign against his Rohilla allies and how Hyder Ali defeated the British during the Battle of Pollilur.