Complex sentence: Adlon's revamped place served famous international treats, highlighting the "Bouillabaisse" specialty, and the business yielded 6,000 daily goldmarks, whereas it once hosted William II, whose ensuing friendship meant Adlon's definitive belonging into the German high society.
Split into simpler sentences: Adlon's revamped place served famous international treats, highlighting the "Bouillabaisse" specialty, and the business yielded 6,000 daily goldmarks. Furthermore, it once hosted William II, whose ensuing friendship meant Adlon's definitive belonging into the German high society.