To assert his suzerainty over Wallachia and Moldavia, he decided to dethrone Prince Radu Șerban of Wallachia; however, the royal council and Michael Weiss (mayor of the important Transylvanian Saxon town of Brassó, now Brașov in Romania) dissuaded him. Radu Șerban voluntarily swore fealty to Gabriel in the presence of his envoys on 31 May. On 18 July, thirteen-year-old Prince of Moldavia Constantin I Movilă also acknowledged Gabriel's suzerainty and promised to pay a yearly tribute of 8,000 florins. That month, Gabriel visited Brassó. His feasts infuriated the burghers, who called him a drunkard or a greedy new Sardanapalus in defamatory poems. Gabriel's promiscuity was notorious; he reportedly seduced young women and promoted noblemen who were willing to offer him their wives.