Complex sentence: Ivan Pavlov, the eldest of eleven children, was born in Ryazan, now in the Central Federal District of Russia, where his father, Peter Dmitrievich Pavlov (1823--1899), was a village priest.
Split into simpler sentences: Ivan Pavlov, the eldest of eleven children, was born in Ryazan (now the Central Federal District) of Russia. His father, Peter Dmitrievich Pavlov (1823--1899), was a village priest.