Simplify the following text for a Grade 7 native English-speaking person.
Original: In the following years Walter 's conducting reputation soared as he was invited to conduct across Europe â `` in Prague , in London where in 1910 he conducted Tristan und Isolde and Ethel Smyth 's The Wreckers at Covent Garden , and in Rome .
Simplified: He was becoming very famous all over Europe . He performed in Prague and in London where in 1910 he conducted Tristan und Isolde and Ethel Smyth 's The Wreckers at Covent Garden .