CAERMARTHEN, a town of Wales, and capital of the county of that name. It is situated on the river Fowey, over which it has a fine stone bridge. It is of great antiquity, being the Maridunum of Ptolemy. It is a populous, thriving, and polite place, many of the neighbouring gentry residing there in the winter. It is a corporation and county of itself, with power to make by-laws. Here were held the courts of chancery and exchequer for South Wales, till the whole was united to England in the reign of Henry VIII. Here was born the famous conjurer Merlin; and near the town is a wood called Merlin's grove, where he is said to have often retired for contemplation. Many of his pretended prophecies are still preserved in the country. The town gives the title of marquis to his grace the duke of Leeds. It sends one member to parliament, and the county another.