Complex sentence: In 1928, Horch formed a corporation, Master Building, Inc., with himself as president, to plan and construct a skyscraper to replace the mansion in which the museum, Institute, and outreach center were located.
Split into simpler sentences: In 1928, Horch formed a corporation, Master Building, Inc., in which he was president. The corporation was appointed to plan and construct a skyscraper to replace the mansion in which the museum, institute, and outreach center were located.