"Initially the military balance was perilous as the Irregulars held sway over most of the west and south of Ireland. Even in Dublin, they had not been decisively defeated, rather they had gone to ground. The Free State's two main port cities, Limerick and Cork, were under the control of the Irregulars, and the River Shannon was beyond the Dublin government's control. It was General Michael Brennan, the Free State military commander in the Limerick area, who correctly summed up the situation: "the Shannon was a barricade and whoever held Limerick held the South and the West." Gen. Brennan firmly believed and with much justification that the outcome of the Irish Civil War turned on Limerick. The Irregulars, although numerically stronger and in possession of most of the Free State territory, did not move on Dublin. They surrendered the initiative to the National Army's forces and embarked on a systematic plan of destruction of all communications and anything that might be of assistance to the Free State army. In the course of this campaign of destruction, which in the words of the Conference of Roman Catholic Bishops "wrecked Ireland from end to end", the country's transport infrastructure was devastated: 236 bridges were damaged, 468 railway locomotives, carriages and other rolling stock were destroyed. The great railway viaduct over the Blackwater at Mallow linking Cork with the north was blown up. The reign of anarchy, which left factories and creameries destroyed and period mansion houses with their priceless art treasures burnt out, obliged the Provisional government to restore order as quickly as possible. In order to avoid a zone of isolation being created beyond the effective jurisdiction of Dublin, military formations were to be moved by sea thus avoiding a long and possibly costly overland advance."