Complex sentence: Luis joined the legation as his personal secretary and assumed duties as a trade commissioner; in the course of his work he visited the royal courts of Berlin and Vienna as well as those of the other capital cities in Central Europe.
Split into simpler sentences: Luis joined the legation as his personal secretary and assumed duties as a trade commissioner. In the course of his work, he visited the royal courts of Berlin and Vienna as well as the courts of the other capital cities in Central Europe.