From Historical Synthesis of the Order of the Blessed Virgin Mary of Mercy:
With the bull Devotionis vestrae, on January 17, 1235, in Perugia, Pope Gregory IX canonically incorporated the new Order in the universal Church. For that reason, with its brief text and simple structure, this bull is especially important for the Order’s history. Some fundamental elements proceed from it.
When the bull was sent, the Order of Mercy already existed as an organized religious institution with its Master and its brothers living together like the military orders and it was known as the House of Saint Eulalia of Barcelona.
The Order had requested the bull. In fact, it was addressed to the Master, namely to Peter Nolasco and to his brothers as the response to the plea sent to the pope.
In addition, the bull presupposed that the said religious organization was functioning with the approbation of the appropriate diocesan authority. If the Roman Pontiff had not had reliable documents to that effect, he would not have granted the confirmation bull.
Likewise, it presupposed that from its foundation in 1218, the Order of Mercy was following the Rule of Saint Augustine in what pertained to the organization of life in common. However, it had not yet been officially incorporated in any of the religious institutions approved by the Church. In fact, at the time, the religious institutions approved by the Church formed several groups according to the Rule which they observed in keeping with the dispositions of the Fourth Lateran Council: the group observing the Rule of Saint Basil, the group following the Rule of Saint Augustine, the group serving under the Rule of Saint Benedict and the group of those who had their own Rules with the approbation of the Holy See. This bull ratified the addition of the Order of Mercy to the group of religious institutions which observed the Rule of Saint Augustine.