Complex sentence: To counter the threat, the Russian General von Toll ordered his Grand Battery to advance some closer to the Poles, but this exposed his flank to Polish guns hidden to the south, near the road to Kraków.
Split into simpler sentences: To counter the threat, the Russian General von Toll ordered his Grand Battery to advance closer to the Poles. This exposed his flank to Polish guns hidden to the south, near the road to Kraków.