Phaulkon's closeness to the king naturally earned him the envy of some Thai members of the royal court, which would eventually prove to be his undoing. When King Narai became terminally ill, a rumor spread that Phaulkon wanted to use the designated heir, Phra Pui, as a puppet and actually become ruler himself. As unlikely as this was, it provided an excuse for Pra Phetracha, the foster brother of Narai to stage a coup d'état, the 1688 Siamese revolution. Without the king's knowledge, both Phaulkon and his followers as well as the royal heir were arrested and executed on June 5, 1688 in Lopburi. When King Narai learned what had happened, he was furious—but was too weak to take any action. Narai died several days later, virtually a prisoner in his own palace. Phetracha then proclaimed himself the new king of Siam and began a xenophobic regime which expelled almost all foreigners from the kingdom.