Thadeus I
| Name | Thadeus I |
| Full name | Thadeus Velor Constantine |
| Succession | Staynish Monarchs; Caltharusian Monarchs |
| Reign | 2 April 1897 – 1 August 1917 |
| Coronation | 2 April 1897 |
| Predecessor | Rosamund II |
| Successor | Thadeus II |
| Marriage | |
| House | Constantine |
| Father | |
| Mother | Rosamund II |
| Born | 3 June 1871 Sani Bursil Royal Palace, Sani Bursil |
| Died | 1 August 1917 Sani Bursil Royal Palace, Sani Bursil |
| Religion | Jubliakese |