1. Japanese Monarchy 600 BC-Present 2,600 Years
2. Cambodia Monarchy 69-Present 1,444 Years
3. Oman Monarchy 751-Present 1,262Years
4. British Monarchy 800-Present 1,200 Years
5. Norway Monarchy 862-Present 1151 Years
6. Luxembourg 922-Present 1,081 Years
7. Denmark Monarchy...