In 1829, Bériot took him to Paris where he made a successful concert debut, again with a concerto by Rode, but he had to return the next year because of the July Revolution and Bériot's marriage to his mistress Maria Malibran and departure on concert tour. Back in Brussels, Vieuxtemps continued developing his violin technique on his own, his musicianship deepened by playing with the deeply musical mezzo-soprano Pauline Viardot, Malibran's sister. A tour of Germany in 1833 brought friendship with Louis Spohr and with Robert Schumann, who compared the boy to Niccolò Paganini. During the following decade he visited various European cities, impressing with his virtuosity not only audiences but also famous musicians such as Hector Berlioz and Paganini himself, whom he encountered at his London debut in 1834.