The writings of the Greek astronomer and cartographer Ptolemy provide perhaps the earliest reference to human habitation in the area now known as Dublin. In around AD 140 he referred to a settlement he called Eblana Civitas. The settlement 'Dubh Linn' dates perhaps as far back as the 1st century BC and later a monastery was built there, though the town was established in about 841 by the Norse. The modern city retains the Anglicised Irish name of the former and the original Irish name of the latter.
Dublin was ruled by the Norse for most of the time between 841 and 999, when it was sacked by Brian Boru, the King of Cashel. Although Dublin still had a Norse king after the Battle of Clontarf in 1014, Norse influence waned under a growing Celtic supremacy until the Norman invasion of Ireland which was launched from Wales in 1169–1172. The last high king (Ard Rí) of Dublin also had local city administration via its Corporation from the Middle Ages. This represented the city's guild-based oligarchy until it was reformed in the 1840s on increasingly democratic lines. In 1348, the city was hit by the Black Death, a lethal plague that ravaged Europe in the mid-14th century.
From the 17th century the city expanded rapidly, helped by the Wide Streets Commission. The population grew from about 10,000 in 1600 to over 50,000 in 1700, and this in spite of another plague epidemic in 1649–51. Georgian Dublin was, for a short time, the second city of the British Empire after London and the fifth largest European city. Much of Dublin's most notable architecture dates from this time. In 1759, the founding of the Guinness brewery at St. James's Gate resulted in a considerable economic impact for the city. For much of the time since its foundation, the Guinness brewery was the largest employer in the city but Catholics were confined to the lower echelons of employment at Guinness and only entered management level in the 1960s. After Irish independence the Guinness Corporate headquarters were moved to London in the 1930s to avoid Irish taxation and a rival brewery to Dublin was opened in London at Park Royal to supply the UK. In 1742 Handel's "Messiah" was performed for the first time in New Musick Hall in Fishamble Street with 26 boys and five men from the combined choirs of St.Patrick's and Christ Church cathedrals participating.
After the Act of Union, 1800, the seat of government moved to the Parliament of the United Kingdom in London. Dublin entered a period of decline, but remained the centre of administration and a transport hub for much of Ireland. Dublin played no major role in the Industrial Revolution. Ireland had no significant sources of coal, the fuel of the time, and Dublin was not a centre of ship manufacture, the other main driver of industrial development in Britain and Ireland. Belfast developed faster than Dublin during this period on a mixture of international trade, factory-based linen cloth production and shipbuilding.
The Easter Rising of 1916, the War of Independence (Anglo-Irish War), and Irish Civil War resulted in a significant amount of physical destruction in the city centre. The Government of the Irish Free State rebuilt the city centre and located the new Oireachtas (Parliament) in Leinster House. Since the beginning of Anglo-Norman rule in the 12th century, the city has functioned as the capital in varying geopolitical entities: Lordship of Ireland (1171–1541), Kingdom of Ireland (1541–1800), island as part of the United Kingdom of Great Britain and Ireland (1801–1922), and the Irish Republic (1919–1922). From 1922, following the partition of Ireland, it became the capital of the Irish Free State (1922–1949) and now is the capital of the Republic of Ireland. One of the memorials to commemorate that time is the Garden of Remembrance.
Since 1997, the landscape of Dublin has changed immensely, with enormous private sector and state development of housing, transport, and business. (see also Development and Preservation in Dublin). Some well-known Dublin street corners are still named for the pub or business which used to occupy the site before closure or redevelopment.