When his uncle Radu assumed the throne upon the death of King Letholdus Stirling II, the infant Cassius II was spirited away by his mother Elisabeta, who feared he would be killed or imprisoned. The two lived in hiding for the next twelve years, until Radu was assassinated.
The fourteen year old Cassius revealed himself upon Radu's death and took the throne. He married Margot Castile, who bore him three children: Letholdus Stirling III, Odette Stirling, and Stephen Stirling. His twenty three year rule was largely uneventful and is considered a period of relative peace.