Constantin Or Constance (Faulcon), also Phatjlcon or Paulcon, a Greek adventurer, born at Custode, in the island of Cephalonia, in 1648, put to death in Siam in June, 1688. Engaged in commercial ventures in the East Indies, he was several times shipwrecked, and on one such occasion, when thrown on the coast of Malabar, met an ambassador of the king of Siam, who had also been shipwrecked. Constantin helped him to reach Siam, and in return received an appointment at the Siamese court. After the death of the prime minister, Constantin became the ruling spirit of that country. Threatened by the jealousy of the mandarins, he sought the assistance of France. In 1685 Louis XIV. despatched the chevalier de Chaumont as ambassador to Siam, while Siamese ambassadors were sent to France. The object of their negotiations appears to have been the subjection of Siam to French rule, with Constantin as viceroy. He was made a French citizen, with the promise of the title of count, and a small force was sent out to aid him in his designs. It arrived in October, 1687, and Bangkok and Mergui were surrendered to its commander; but the native nobles raised an insurrection, and having captured Constantin had him put to death for treason.

His son afterward acquired considerable influence in Siam. The adventures of Constantin have been written by Deslandes (Histoire de Constance, premier ministre du roi de Siam, Amsterdam, 1756), and by Gal-lois in the Moniteur (Paris, 1853).