Complex sentence: In 1956 she released a new version of the standard Mambo Italiano, which went on to become her greatest hit, while in 1957 she released the song "La Casetta in Canada".
Split into simpler sentences: In 1956 she released a new version of the standard Mambo Italiano, which went on to become her greatest hit. In 1957 she released the song "La Casetta in Canada".