The five Belgian violinists mentioned in the crossword solutions are Eugène Ysaÿe, Henri Vieuxtemps, Efrem Zimbalist, Isaac Stern, and Mischa Elman. Ysaÿe was a renowned composer and virtuoso violinist who was known for his six solo sonatas for violin. Vieuxtemps was a composer and violinist who wrote five concertos for violin. Zimbalist was a Russian-American violinist and teacher who was known for his interpretations of Bach and Beethoven. Stern was an American violinist who was known for his recordings of the Beethoven and Brahms violin concertos. Elman was a Ukrainian-born American violinist who was known for his sweet tone and lyrical playing. Lastly, Leopold AUER was a Hungarian-born violinist and teacher who was known for his teaching methods and his students, which included Jascha Heifetz and Mischa Elman.