Complex sentence: Following the armistice of Italy on September 8 1943, the "Xª MAS" was disbanded, and some of its sailors joined the Allied cause to fight against Nazi Germany and what remained of the Axis.
Split into simpler sentences: Following the armistice of Italy on September 8 1943, the "Xª MAS" was disbanded. Some of its sailors joined the Allied cause to fight against Nazi Germany and what remained of the Axis.