When the French invaded the Dutch Republic in May 1672, they initially seemed to have achieved an overwhelming victory, following a fast advance to the Rhine quickly capturing the major Dutch fortresses of Nijmegen and Fort Crèvecœur near 's-Hertogenbosch after having occupied Utrecht without a fight. However, by late July, the Dutch position stabilised behind the Holland Water Line and concern at French gains brought them support from Brandenburg-Prussia, Emperor Leopold and Charles II of Spain. This forced Louis to divide his forces; in August 1672, he sent his best general Henri de La Tour d'Auvergne, Viscount of Turenne with 50,000 troops to the Rhineland.