Merthyr Tydfil County Borough: History
=== Pre-industrial Merthyr ===
What is now Merthyr Tydfil town centre was originally little more than a village. An ironworks existed in the parish in the Elizabethan period, but it did not survive beyond the early 1640s at the latest. In 1754, it was recorded that the valley was almost entirely populated by shepherds. Farm produce was traded at many markets and fairs, notably the Waun Fair above Dowlais.
==== Influence and growth of iron industry ====
What is now Merthyr Tydfil County Borough was situated close to reserves of iron ore, coal, limestone and water, making it an ideal site for ironworks. Small-scale iron working and coal mining had been carried out at some places in South Wales since the Tudor period, but in the wake of the Industrial Revolution the demand for iron led to the rapid expansion of Merthyr's iron operations in the northern half of the County Borough. The Dowlais Ironworks was founded by what would become the Dowlais Iron Company in 1759, making it the first major works in the area. It was followed in 1765 by the Cyfarthfa Ironworks. The Plymouth Ironworks were initially in the same ownership as Cyfarthfa, but passed after the death of Anthony Bacon to Richard Hill in 1788. The fourth ironworks was Penydarren built by Francis Homfray and Samuel Homfray after 1784.
The demand for iron was fuelled by the Royal Navy, who needed cannon for their ships, and later by the railways. In 1802, Admiral Lord Nelson visited Merthyr to witness cannon being made.
Several railway companies established routes that linked Merthyr with coastal ports or other parts of Britain. They included the Brecon and Merthyr Railway, Vale of Neath Railway, Taff Vale Railway and Great Western Railway. They often shared routes to enable access to coal mines and ironworks through rugged country, which presented great engineering challenges. In 1804, the world's first railway steam locomotive, "The Iron Horse", developed by the Cornish engineer Richard Trevithick, pulled 10 tons of iron on the newly constructed Merthyr Tramway from Penydarren to Abercynon. A replica of this now resides in the National Waterfront Museum in Swansea. The tramway passed through what is arguably the oldest railway tunnel in the world, part of which can still be seen alongside Pentrebach Road at the lower end of the town.
The 1801 census recorded the population of Merthyr as 7705, the most populous parish in Wales (however, the built-up area of Swansea, covering several parishes, then exceeded 10,000). By 1851 Merthyr had overtaken Swansea to become the largest town in Wales with 46,378 inhabitants. By this time, Irish immigrants made up 10% of the local population, and there were substantial numbers of English, together with some Spaniards and Italians. A Jewish community was established some time after 1841, and by 1851, they were able to establish a small prayer hall. The charming Merthyr Synagogue was consecrated in 1875 and a cemetery at Cefn-Coed was established in the 1860s.
During the first few decades of the 19th century, the ironworks at Dowlais and Cyfarthfa continued to expand and at their peak were the most productive ironworks in the world. 50,000 tons of rails left just one ironworks in 1844, to enable expansion of railways across Russia to Siberia. At its peak, the Dowlais Iron Company operated 18 blast furnaces and employed 7,300 people, and by 1857 had constructed the world's most powerful rolling mill. …