Complex sentence: The road to Madrid lay open to Joseph, and the failures at Gerona, Valencia, and Saragossa were forgotten; all that remained was to reinforce Dupont and allow him to force his way south through Andalusia.
Split into simpler sentences: The road to Madrid lay open to Joseph, and the failures at Gerona, Valencia, and Saragossa were forgotten. All that remained was to reinforce Dupont and allow him to force his way south through Andalusia.