Complex sentence: Masséna's forces arrived at the Lines on 11 October and shortly afterwards stormed Sobral de Monte Agraço but were repulsed in the attempt to assault of Forte de Alqueidão (Alqueidão Fort), a second bigger and better equipped redoubt.
Split into simpler sentences: Masséna's forces arrived at the Lines on 11 October and shortly afterwards stormed Sobral de Monte Agraço. They were repulsed in an attempt to assault Forte de Alqueidão (Alqueidão Fort), a bigger and better equipped redoubt.