Complex sentence: Although there were periods of times when the letters would cease altogether, in total Farley sent about two hundred letters over period of four years, with his last letter sent from his prison cell after his rampage at ESL.
Split into simpler sentences: Although there were periods of times when the letters would cease altogether, in total Farley sent about two hundred letters over period of four years. His last letter from from his prison cell after his rampage at ESL.