In 1923, Bishop Perros, Bishop of the Diocese of Siam had written to Bishop Fairy, Councilor of the Ministry of Propaganda, showing his desire to have the Congregation of Sisters to come to strengthen and spread the religion.

Bishop Fairy recently asked three Ursuline Sisters from Canada to lay the foundation in Shantou, China, and therefore sent the letter to Mother Superior Vinifrid and the letter was forwarded to Mother Superior Marie du Roche in Shantou. Mother Du Roche, reading Bishop Fairy's letter carefully and began the direct contact with Bishop Perros.

Bishop Perros offered the Ursulines to begin work at the diocesan school which had been taught in Chinese and Thai language before. There would be a Thai teacher to help teach the students while the sisters had to learn Thai and he informed that the sisters did not have to worry about the expenses. After that, Mother Du Roche and the bishop had a letter to the Mother General of the Ursulines in Rome which did not immediately receive an answer. Mother then wrote again with another letter, recommending Sister Marie Bernard Mancelle, a French sister who was then based in Java, as responsible for the group going to Siam because she was someone who had been in contact and had some kindness.

Several months passed Mother Du Roche finally received the news from Mother General of the Ursulines in Rome, accepting the request and preparing to send four missionaries, selected from four volunteers who originally would go to China from three countries: France, Belgium and Yugoslovia, they were Sister Marie Therese Mertens, the head, Sister Marie Xaveria Pirc, Sister Marie Raphaela Vurnik and Sister Agnes Delattre.