 The Prince also issued a ban on Greek immigration, though he was still lenient toward naturalized Greeks; he ended some of the privileges granted to Mount Athos, and made foreigners subject to taxation, while also reinforcing special rules against the social integration of Muslim converts.Such measures failed to convince the boyar rebels, who organized an invasion of Wallachia from over the border, in the Principality of Transylvania.They managed to occupy Oltenia and threatened Bucharest, but were routed by Leon in August 1631.