Formal relations between Siam and the Vatican date to 1669 when Pope Clement IX sent a papal brief to King Narai. Informal relations began earlier with the arrival of the Portuguese and their priests. King Narai responded with two missions to Rome but only the second arrived in late 1688. The events behind these missions are related by historian Michael Smithies, assisted by the former Apostolic Nuncio of Bangkok, Mgr. Bressan.