Saint Piran is the patron saint of tin miners.
The flag of St Piran (or St Perran) features a white cross on a black background. This symbolises the tin metal set in a black background of charcoal ashes and represents contemporary Cornish pride in a sense of identity .
Saint Piran is supposed to have rediscovered tin-smelting when his black hearthstone, which was evidently a slab of tin bearing ore, from his fire caused some white tin to melt into the shape of a cross. It is this white cross on a black background that is now the recognised symbol of Cornwall.
St Piran's feast day is the 5th March and is celebrated worldwide wherever there are Cornish people.