The Philatelic and Numismatic Office of Vatican will celebrate this year the 350th Anniversary of the Synod of Ayutthaya. In 1658 the then Congregation for the Propagation of the Faith chose François Pallu, Pierre Lambert and Ignace Cotolendi to direct evangelization efforts in Asia. The three French missionaries travelled for a number of years, often in disguise, in order to avoid persecution.
They later reached Ayutthaya during the Reign of Siam where there was religious tolerance which allowed for the existence of a small Christian community of around two thousand souls. In 1664 the two Apostolic Vicars, Pallu and Lambert, together with other religious and lay people thought of organizing an assembly to discuss the proper carrying out of apostolic functions in those faraway lands.
They came up with what was called the "Monita ad Missionarios", a series of instructions regarding the conduct of missionaries. The local young people amazed the religious with their intellectual gifts. The results they achieved were greater than those obtained with similarly aged children in Europe.
The postage stamp is a joint issue with the postal administration of Thailand. Depicted on the left side are the missionaries who received their mandate from the Pope, while on the right side are the Church of Saint Joseph of Ayutthaya, a place of Catholic worship in Thailand with more than 300 years of living testimony to the work of evangelization. In 2008 Pope Benedict XVI paid tribute to the commitment and dedication of those who at times had to make the ultimate sacrifice in the work of evangelization in those lands: "Many missionaries have gone to great lengths to witness to the love of God among the peoples of Asia, and at times, in a heroic manner."