In Europe he sang in many opera houses, including Vlaamse Opera and La Scala in Milan.
József Beck | Gregor Schlierenzauer | Gregor Piatigorsky | Gregor Mendel | Gregor Schneider | Jozsef Gregor | József Antall | Gregor Wentzel | Gregor Gysi | Attila József | Nora Gregor | József Alvinczi | Gregor Ziemer | Gregor MacGregor | Gregor Benko | József Eötvös | József Bozsik | Gregor Žerjav | Gregor Kiczales | Gregor Gall | Gregor Edmunds | Gregor Collins | Francis Gregor (MP) | Francis Gregor | Clan Gregor | A. James Gregor | József Vass | József Tóth (geographer) | József Somogyi | József Sándor Krenner |
Artists who have appeared with the company include the conductors, Donato Cabrera, David Giménez Carreras, and Christopher Larkin; and the singers Klara Barlow, Gregory Reinhart, Marcello Giordani, Charles Castronovo, and Jozsef Gregor.