Stannary law (derived from the for tin) is the body of English law that governs tin mining in Devon and Cornwall; although no longer of much practical relevance, the stannary law remains part of the law of the United Kingdom and is arguably the oldest law incorporated into the English legal system. The stannary law's complexity and comprehensive reach into the lives of tin miners necessitated the existence of the legislative Stannary Convocations of Devon and Cornwall, the judicial Courts of the Vice-Warden of the Stannaries, and the executive Lord Warden of the Stannaries. The separate and powerful government institutions available to the tin miners reflected the enormous importance of the tin industry to the English economy during the Middle Ages. Special laws for tin miners pre-date written legal codes in Britain, and ancient traditions exempted everyone connected with tin mining in Cornwall and Devon from any jurisdiction other than the stannary courts in all but the most exceptional circumstances. Stannary Convocation of Devon Edward I's 1305 Stannary Charter established Tavistock, Ashburton and Chagford as Devon's stannaries, with a monopoly on all tin mining in Devon, a right to representation in the Stannary Parliament and a right to the jurisdiction of the stannary courts. Plympton became the fourth Devon stannary town in 1307. The parliament consisted of ninety-six jurates, with twenty-four being chosen by each of the four Devon stannaries. The jurates were chosen at special courts held in each stannary by "tinners": a term broad enough to include not just miners and tin work owners, but others concerned with the tin industry. The Parliament usually met in an open air forum at Crockern Tor. The last convocation of the Devon Parliament was in 1786, but as late as the 1980s, an honorary stannator would be named whenever a new tin mine was opened. Cornish Stannary Parliament A charter of King John had given the tin miners of Cornwall certain legal rights which were confirmed by King Edward I in 1305. They had the rights of "bounding" (prospecting for and working tin ore deposits), of trial before their own stannary court, and of exemption from ordinary taxation. The stannaries were: Foweymore (district of Bodmin Moor), Blackmore (district of St Austell); Tywarnhayle (district of St Agnes and Carn Brea); and Kerrier and Penwith (district between Godolphin and Land's End). The courts were normally held every three weeks and presided over by