Complex sentence: Soon after the German takeover of Jedwabne in July 1941 a group of 300 Jews with families were rounded up by Nazi Germans and locked in a barn, which was then set on fire by Polish men in their presence.
Split into simpler sentences: Soon after the German takeover of Jedwabne in July 1941, the Jedwabne pogrom took place. About 300 members of Jewish families were rounded up by Nazi Germans and locked in a barn, which was then set on fire by Polish men in their presence.