The earliest source that does state that Cissa was king is that of the Anglo-Norman chronicler, Henry of Huntingdon, who wrote between 1130 and 1154, and clearly used his imagination to fill out gaps in the historical record.
A fonte máis temperá que declara que Cissa foi rei pertence ao cronista anglo-normando Henrique de Huntingdon, quen escribiu entre 1130 e 1154, e que claramente utilizou a súa imaxinación para cubrir as brechas existentes na historia.