Complex sentence: In 1939 the invading forces totalled 1.5 million Germans, and nearly half a million Soviets, engaged in parallel campaigns of destruction purposed to eradicate the existence of a sovereign Poland, its cultural heritage and citizens.
Split into simpler sentences: In 1939 the invading forces totalled 1.5 million Germans, and nearly half a million Soviets. Both regimes engaged in campaigns of destruction purposed to eradicate the existence of a sovereign Poland, its cultural heritage and citizens.