According to Rod Lyon's "Cornwall's Historical Wars: A Brief Introduction" The Cornish Stannary Parliament was chartered in 1201, by King John. In spite of the name the Parliament was not a national assembly. The charter granted special rights to "tinners" - those involved in mining Tin, and exempted them taxes and dues, while they were working in the Tin industry. Tinners were also protected from being called up to provide labour to local lords of the manor - while they were working in the Tin industry. The Stannary Parliament's authority was confined to matters related to the Tin industry.
Members of the Stannary Parliament were called "Stannators". There were 24 Stannators.