This "little gem of Gothic architecture" with its coach house for the Hibbert's' horses, carriage and groom - he was even provided with a fire on cold days - served the Catholics well, but in turn became too small. On feast days and at harvest time, the sermon was given from the large stone cross in the churchyard as there was not enough room for all who wanted to go into the church. Sometimes tickets were issued for admission on feast days, especially then non-Catholic townspeople came in large numbers to these services.
Before any further extension of St. Marie's took place, some very significant developments occurred. Captain Hibbert met and came to admire Father Luigi Gentili. Gentili was a member of the Institute of Charity (usually referred to as the Rosminians) sent as a missionary to England by Antonio Rosmini Serbati, the founder of the order.
Father Gentili and his companions carried out very successful Missions in the Midlands and often stayed with the Hibbert's. Probably Captain Hibbert's long discussions with Father Gentili on the Catholic Faith helped him to decide to become a Catholic. He was received into the Church on 16th July 1846. Captain Hibbert subsequently asked Bishop Ullathorne and Father Pagani, the English Provincial of the Rosminians if the Institute of Charity could take over St. Marie's. This was approved and two Rosminian priests and four lay brothers came to Rugby in 1849. The Institute of Charity serves St. Marie's to this day