Cardiff has been a port for many hundreds of years, but it was not until the nineteenth century that it began to enjoy a large quantity of trade.
The first documented mention of a quay at Cardiff occurs in the sixteenth century, although it is likely that maritime trade was occurring here for centuries prior to this.
During the seventeenth and eighteenth centuries, although Cardiff was the head port of the Monmouthshire and Glamorgan Coast, the rival port of Swansea was much more important in terms of shipping and commerce. In 1796, Swansea’s registered tonnage was 4,929 tons, nearly five times Cardiff’s 1,069 tons. Much of this was to do with minerals, as metallurgical industry developed earlier near Neath and Swansea, and coal-mining developed in West Glamorgan, Carmarthen and Pembrokeshire before the mineral wealth of the South Wales Valleys began to be exploited.
In 1791, the Glamorgan Canal Act was passed, allowing a canal to be built to serve the iron manufacturing industry that was newly developing at the heads of the Taff valleys. These areas were ideally suited for iron-manufacturing as they had extensive forests to provide charcoal, along with nearby sources of ironstone, limestone, coal and water. Transporting the iron to Cardiff, the nearest accessible port, was costly and slow until the construction of the canal however. The Canal was extended by an Act of 1796, which permitted the construction of a sea lock. This permitted further development of ironworks and collieries in the Merthyr area.
The Canal quickly became inadequate for the amount of traffic, and action was taken during the 1830s to provide more efficient transportation and improved harbour facilities. In 1839, the West Bute Dock opened. It was funded by the Second marquess of Bute, who was the major landowner in the area. His lands contained huge mineral reserves, and in order to successfully exploit these he needed to ensure his tenants had adequate facilities. At the same time, the Merthyr ironmasters formed the Taff Vale Railway Company and constructed a railway from Merthyr Tydfil to Cardiff.