Much of the wider area was laid waste in the subsequent Harrying of the North. After the Roman withdrawal and Saxon conquest, the focus of settlement shifted to the confluence of the Irwell and Irk sometime before the arrival of the Normans after 1066.
The Roman habitation of Manchester probably ended around the 3rd century its civilian settlement appears to have been abandoned by the mid-3rd century, although the fort may have supported a small garrison until the late 3rd or early 4th century. A stabilised fragment of foundations of the final version of the Roman fort is visible in Castlefield. Central Manchester has been permanently settled since this time. Following the Roman conquest of Britain in the 1st century, General Agricola ordered the construction of a fort named Mamucium in the year 79 to ensure that Roman interests in Deva Victrix ( Chester) and Eboracum ( York) were protected from the Brigantes. Their territory extended across the fertile lowland of what is now Salford and Stretford. The Brigantes were the major Celtic tribe in what is now known as Northern England they had a stronghold in the locality at a sandstone outcrop on which Manchester Cathedral now stands, opposite the bank of the River Irwell. The suffix -chester is from Old English ceaster ("Roman fortification", itself a loanword from Latin castra, "fort fortified town"). Both usages are preserved in Insular Celtic languages, such as mam meaning "breast" in Irish and "mother" in Welsh.
However, more recent work suggests that it could come from * mamma ("mother", in reference to a local river goddess). The generally accepted etymology of this name is that it comes from Brittonic * mamm- (" breast", in reference to a " breast-like hill"). These names are generally thought to represent a Latinisation of an original Brittonic name. The name Manchester originates from the Latin name Mamucium or its variant Mancunio and the citizens are still referred to as Mancunians ( / m æ n ˈ k juː n i ə n/). Williams, Tom Kilburn and Geoff Tootill developed the world's first stored-program computer in 1948, and Andre Geim and Konstantin Novoselov isolated the first graphene in 2004. At the University of Manchester, Ernest Rutherford first split the atom in 1917, Frederic C. Manchester Liverpool Road railway station was the world's first inter-city passenger railway station. The city is notable for its architecture, culture, musical exports, media links, scientific and engineering output, social impact, sports clubs and transport connections. Following successful redevelopment after the IRA bombing, Manchester was the host city for the 2002 Commonwealth Games. Its fortune declined after the Second World War, owing to deindustrialisation, but the IRA bombing in 1996 led to extensive investment and regeneration. The Manchester Ship Canal opened in 1894, creating the Port of Manchester and linking the city to the Irish Sea, 36 miles (58 km) to the west. Manchester's unplanned urbanisation was brought on by a boom in textile manufacture during the Industrial Revolution, and resulted in it becoming the world's first industrialised city. Throughout the Middle Ages Manchester remained a manorial township, but began to expand "at an astonishing rate" around the turn of the 19th century. Historically part of Lancashire, areas of Cheshire south of the River Mersey were incorporated into Manchester in the 20th century, including Wythenshawe in 1931. The history of Manchester began with the civilian settlement associated with the Roman fort ( castra) of Mamucium or Mancunium, established in about AD 79 on a sandstone bluff near the confluence of the rivers Medlock and Irwell. The two cities and the surrounding towns form a large continuous conurbation. It is fringed by the Cheshire Plain to the south, the Pennines to the north and east and the neighbouring city of Salford to the west. Manchester ( / ˈ m æ n tʃ ɪ s t ər, - tʃ ɛ s-/) is a city in Greater Manchester, England, with a population of 547,627 in 2018. Manchester Cathedral, a grade I listed building which is the Anglican cathedral and parish church of Manchester and the mother church of the Diocese of Manchester