Complex sentence: The establishment of concentration camps was entrusted to the Cheka, with Dzerzhinsky orchestrating their construction from the spring of 1919 onward, although they would subsequently be administered by a new government agency, Gulag.
Split into simpler sentences: The establishment of concentration camps was entrusted to the Cheka, with Dzerzhinsky orchestrating their construction from the spring of 1919 onward. They would subsequently be administered by a new government agency, Gulag.