Complex sentence: One year after his wedding, Carl and his sister Hermine founded a limited company, which she left three years later and from that time Carl Kracht was the sole owner of the hotel in the heart of Cologne.
Split into simpler sentences: One year after his wedding, Carl Kracht and his sister Hermine founded a limited company, which she left three years later. From that time Carl Kracht was the sole owner of the hotel in the heart of Cologne.