Complex sentence: After a three weeks carnival of blood and debauchery Razin quit Astrakhan with two hundred barges full of troops to establish the Cossack republic along the whole length of the Volga, as a preliminary step towards advancing against Moscow.
Split into simpler sentences: After a three-week carnival of blood and debauchery Razin quit Astrakhan with two hundred barges full of troops. His aim was to establish the Cossack republic along the whole length of the Volga as a preliminary step towards advancing against Moscow.