By the 1520s, Chiprovtsi was still a minor centre of mining activity compared to other places in the empire. In that period, it brought a revenue of 47,553 "akçe", as compared to Kratovo's 100,000 and Srebrenica's 477,000. The Catholic miners are known to have arrived by that time, as the Catholic Church of Saint Mary had been built around 1487, but it was not until the years after the 1520s that Chiprovtsi attracted more colonists and turned into one of the Ottoman Empire's leading mining centres. By 1528, Chiprovtsi had a mint and was manufacturing silver coins. In 1585, the miners were forced to work night and day and had to pay increased taxes, leading to protests and the danger that they may migrate. By the time, Chiprovtsi was already providing a revenue of 1,400,000 "akçe", making it one of the empire's prime mining and metalworking regions.