Following the First Mongol invasion of Hungary, King Béla IV ordered the construction of reinforced stone walls around the town of Buda and set his own royal palace on the top of the protecting hills of Buda, creating a new royal capital in the decades between 1247 and 1265. For defensive purposes, he moved the citizens of Pest to a hill on the opposite side of the Danube in 1248. Within two decades their new fortified town, Buda, became the most important center of commerce in Hungary. The emerging burghers, who sought autonomy, had several conflicts with various church institutions in the second half of the 13th century. Around the same time, several German merchants settled in the town. They had several privileges, including duty exemption and free choice of priests. Béla IV granted the collection right of local fair duty and the right of patronage over the Church of Our Lady, which was under construction, to the Dominican nuns at Rabbits' Island in 1255, which seriously harmed the economic interests of the merchants. During the various lawsuits, the prestigious nunnery have enjoyed the support of all political factors, in addition to the Roman Curia, which confirmed its privileges. In 1287, the burghers requested Ladislaus IV to annually hold new nationwide duty-free fairs in the town, but Ladislaus refused this after a few months of hesitation. The protection of the Dominican nuns inhibited the material growth of the burghers. For instance, although "rector" Werner was granted a land donation by the king in the next year, he was not registered as the owner, because the nuns claimed the lands for themselves. Ladislaus' successor, Andrew III also supported the Dominican nuns against the burghers of Buda in various occasions.