thumb|left|Jubilee dock, Cardiff, from the eastern side (1849) The town grew rapidly from the 1830s onwards, when the Marquess of Bute built a dock, which eventually linked to the Taff Vale Railway. Cardiff became the main port for coal exports from the Cynon, Rhondda, and Rhymney valleys, and grew in population at a rate of nearly 80 per cent per decade between 1840 and 1870. Much of this was due to migration from within and outside Wales: in 1841, a quarter of Cardiff's population were English-born and more than 10 per cent born in Ireland. By the 1881 census, Cardiff had overtaken Merthyr and Swansea to become the largest town in Wales. Cardiff's status as the premier town in South Wales was confirmed when it was chosen as the site for the University College of South Wales and Monmouthshire in 1883.
thumb|left|Jubilee dock, Cardiff, from the eastern side (1849) The town grew rapidly from the 1830s onwards, when the Marquess of Bute built a dock, which eventually linked to the Taff Vale Railway. Cardiff became the main port for coal exports from the Cynon, Rhondda, and Rhymney valleys, and grew in population at a rate of nearly 80 per cent per decade between 1840 and 1870. Much of this was due to migration from within and outside Wales: in 1841, a quarter of Cardiff's population were English-born and more than 10 per cent born in Ireland. By the 1881 census, Cardiff had overtaken Merthyr and Swansea to become the largest town in Wales. Cardiff's status as the premier town in South Wales was confirmed when it was chosen as the site for the University College of South Wales and Monmouthshire in 1883.