First appeared in Forbes' ranks at age 8 but officially inherited fortune in June 2001 on his 18th birthday. Went to high school in Rome; in June 2008 received an M.A. in economics and theology from the University of Edinburgh in Scotland. But this prince hardly needs to earn his keep. Assets include real estate, art and a tech company and 30,000 hectares of woodland in Germany, one of the largest forest holdings in Europe. Despite local opposition is apparently going ahead with plans to build one of the world's largest solar farms in Bavaria, southern Germany, to sell electricity. Lives in family castle, Schloss Emmeram. Eligible bachelor is also a race car driver; tours with a German auto-racing league.