Complex sentence: Tactically, the Anglo-Russian forces were successful initially, defeating the defenders in the battles of Callantsoog and the Krabbendam, but subsequent battles went against the Anglo-Russian forces.
Split into simpler sentences: Tactically, the Anglo-Russian forces were successful initially, defeating the defenders in the battles of Callantsoog and the Krabbendam. However, subsequent battles went against the Anglo-Russian forces.