Second Battle of Osgiliath

After many battles in Osgiliath, Sauron finally launched a massive invasion that ultimately resulted in the deciding factor as to who reigned over Osgiliath. All of the Minas Morgul and Haradrim forces were involved in the project, and while there were some soldiers from Rhun and Barad-dur besieging Cair Andros, most of the Easterlings and Barad-dur soldiers also went to Osgiliath. Much of the struggle for Osgiliath was personally overseen by the Witch-King himself, and probably also the Fifth of the Nazgul, and Suladan the Serpent-Lord, as Amdur and possibly Gothmog would have been in Cair Andros, and though in all likelihood would have had a rendeveu in Osgiliath while there was still a battle for Osgiliath, and therefore couldn't have been the main masterminds behind it.

As the Gondorians destroyed or blocked the easiest ways to Osgiliath, the best way to go was by boat. Many of southern forces from Minas Morgul and probably Harad came by deliberately fighting the Anduin current with oars on their boats, a generally unexpected tactic. This caught the Gondorians by surprise and the Modorim invaded easily. Greatly outnumbering the Gondorians, the Gondorians lead by Faramir had to retreat. The victory there made it fairly safe and easy to send more waves of soldiers from Mordor, who were waiting to be summoned; in order to get siege weapons across, the Mordorim partly rebuilt parts of Osgiliath, making it possible to get Grond and the numerous legions waiting across; in fact, there were so many soldiers, that they left behind reserve troops in Osgiliath in case sacking the city needed much manpower or in case an emergency occurred.