Original: When Bron left Russia in 1987 to teach at the Royal Academy of Music (RAM), Vengerov and his mother followed him there, and did so again after Bron moved to Lübeck to open a school there.
Simplified: When Bron left Russia in 1987 to teach at the Royal Academy of Music in London, Vengerov and his mother followed him there. They also followed Bron when he moved to Lübeck to open a school there.