 One of the largest groups of surviving works of art are the seal matrices that appear to have entered Scottish usage with <unk> in the reign of David I , beginning at the royal court and among his Anglo @-@ Norman vassals and then by about 1250 they began to spread to the <unk> areas of the country . They would be made compulsory for barons of the king in a statute of <unk> and seal matrices show very high standards of skill and <unk> . Examples of items that were probably the work of continental artists include the delicate hanging lamp in St. John 's Kirk in Perth , the vestments and <unk> in <unk> and the Medieval <unk> of the Universities of St Andrews and Glasgow . 
