Beginning at the extreme westerly limit of St. Martin's-in-the-Fields, on the south side of Hyde Park Corner, we find ourselves in the Green Park. This is a triangular piece of ground, which was formerly called Little or Upper St. James's Park. It has not much history. In 1642 fortifications were erected on Constitution Hill, and at the end of the seventeenth century this same spot was a noted place for duels. Fireworks on a great scale, with public entertainments, took place in the park at the Peace of Aix-la-Chapelle, and again in 1814.