sentences:  He began his career with major roles in Verdi operas such as the Duke in Rigoletto, Foresto in Attila and Radames in Aida, also Lindoro in Rossini's Italiana in Algeri, Fernando in Donizetti's La Favorita and Pollione in Bellini's Norma.He was equally successful from the beginning as a singer in concerts and oratorios.Tzvetanov continued his studies with Boris Hristov in Rome, Prof. G. Lehmann and Margarita Lilova in Vienna, also with Carlo Bergonzi at the Verdi Academy in Busseto.