Skopje began to recover from decades of decline after 1850. At that time, the city experienced a slow but steady demographic growth, mainly due to the rural exodus of Slav Macedonians. It was also fuelled by the exodus of Muslims from Serbia and Bulgaria, which were gaining autonomy and independence from the Empire at that time. During the Tanzimat reforms, nationalism arose in the Empire and in 1870 a new Bulgarian Church was established and its separate diocese was created, based on ethnic identity, rather than religious principles. The Slavic population of the bishopric of Skopje voted in 1874 overwhelmingly, by 91% in favour of joining the Exarchate and became part of the Bulgarian Millet. Economic growth was permitted by the construction of the Skopje-Salonica railway in 1873. The train station was built south of the Vardar and this contributed to the relocation of economic activities on this side of the river, which had never been urbanized before. Because of the rural exodus, the share of Christians in the city population arose. Some of the newcomers became part of the local elite and helped to spread nationalist ideas Skopje was one of the five main centres of the Internal Macedonian Revolutionary Organization when it organized the 1903 Ilinden uprising. Its revolutionary network in Skopje region was not well-developed and the lack of weapons was a serious problem. At the outbreak of the uprising the rebel forces derailed a military train. On 3 and 5 August respectively, they attacked an Ottoman unit guarding the bridge on the Vardar river and gave a battle in the "St. Jovan" monastery. In the next few days the band was pursued by numerous Bashibozuks and moved to Bulgaria.