Complex sentence: Major-General Baron Anatoly Stoessel defended the siege of Port Arthur, for five months, but the Japanese army managed to sink several Russian ships attempting to relieve him through long-distance fire in early December.
Split into simpler sentences: Major-General Baron Anatoly Stoessel defended the siege of Port Arthur for five months. But the Japanese army managed to sink several Russian ships attempting to relieve him through long-distance fire in early December.