There were four main ironworks in Merthyr, Dowlais, Cyfarthfa, Plymouth and Penydarren. Dowlais and Cyfarthfa were the most influential. Dowlais was founded by Isaac Wilkinson and John Guest in 1759 and Cyfarthfa by Anthony Bacon and William Brownrigg in 1769. These men were already ironmasters who came from elsewhere, attracted to the area by the abundance of both coal and iron ore. The American War of Independence 1776 - 1793 provided a literal fortune derived from war. The Royal Navy had a huge requirement for cannons and cannonballs and Merthyr was willing and ready.