Complex sentence: Grade, the youngest of three brothers, was born in London in 1916, four years after his Jewish family had emigrated from Tokmak, Ukrainethen Imperial Russian territoryin response to pogroms.
Split into simpler sentences: Grade, the youngest of three brothers, was born in London. In 1912, four years prior to his birth, his Jewish family had emigrated from Tokmak, Ukrainethen Imperial Russian territoryin response to pogroms.