Complex sentence: In the 1990s, Jan Delay was best known for being one third of German hip hop pioneers Beginner (formerly Absolute Beginner), nowadays he is a successful solo artist and joined the sideproject "La Boom" together with German songwriter and producer Tropf.
Split into simpler sentences: In the 1990s, Jan Delay was best known for being one third of German hip-hop pioneers Beginner. He is a successful solo artist and has also joined the sideproject "La Boom" together with German songwriter and producer Tropf.