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.
All 4 departed from the port of Marseille, France on October 23rd, 1924, without knowing where Siam was, the weather, the people, and the language or there was something ahead.
Until November 25th, the same year, all 4 Sisters had arrived in Siam. Lived at St. Louis Hospital and started work at Kularb Wattana School, Calvary Church near Talat Noi taking care of orphans, doing parish work, and taking responsibility in school. While having to learn Thai they had adapted to the weather and were also suffering from tropical diseases. This difficult time spanned two years, with a lack of support from both Bangkok and Rome.
In 1926 a General Chapter was held in Rome with the election of Mother General who was Mother Marie de Saint-Jean-Martin who appointed Sister Marie Bernard Mancel from Java as the Superior at Siam.
Mother Bernard Mancel did everything possible to resolve a situation that had been left so hard for a long time. Since the restoration of the relationship, traveled to meet everyone she thought she could help, made a loan to buy the land at the advice of Bishop Perros in order to prepare a school for women and a boarding school etc.
Less than a year Mother Bernard received the approval from Rome to build a school dedicated to the Virgin Mary named Mater Dei in Bangkok which was opened in 1928 by Mother Marie Bernard Mancelle as the first Superior. In 1932 Regina Coeli School opened in Chiang Mai, in 1955 opened Vasudevi School in Bangkok and in 2003 opened Piyamat School in Phayao Province
The Ursulines also operate various activities related to providing various forms of education, the most recent of which the Ursuline sisters have operated is: Opening of the Ursuline House in Cambodia on September 29th, 2010.
Ursuline book of the Roman Union, 1985
Commemorative book 7 cycle 84 years of Mother Theodore Hanenfeld December 23rd, 2006
Book of Religious women and men in Thailand