Dublin Castle Ireland (1800–1922). After the signing of the Anglo-Irish Treaty in December 1921, the complex was ceremonially handed over to the newly formed Provisional Government led by Michael Collins. It now hosts the inauguration of each President of Ireland, and various State receptions. The castle was built by the dark pool ("Dubh Linn") which gave Dublin its name. This pool lies on the lower course of the River Poddle before its confluence with the River Liffey; when the castle was built, the Liffey was much wider, and the castle was effectively defended by both rivers. The Poddle today runs under the
Belfast–Dublin line Belfast–Dublin line The Belfast–Dublin line is a main and busiest railway route on the island of Ireland that connects Dublin Connolly station in the Republic of Ireland and station in Northern Ireland. The railway line was built by three separate companies. In 1837 the Ulster Railway began building a railway line between Belfast and Lisburn, which was extended in stages to Portadown in 1842 and as far as Clones by 1863. The Dublin and Drogheda Railway (D&D) built the line between Dublin and Drogheda. The Dublin and Belfast Junction Railway (D&B Jct) linked the Dublin and Drogheda with the Ulster