When Saint Paul of the Cross, together with his closest collaborators, entered the Basilica-Monastery complex of Sts. John and Paul on the Celio Hill, it was in the late afternoon of 9 December 1773. He came to live in one of the most ancient and venerated Christian sites in Rome.

Since 1768, Paul and a small community lived in the Hospice of the Holy Crucifix located in Via San Giovanni in Laterano. A previous project, which was unsuccessful, of establishing a stable presence in the city of Rome dates back to 1747, when they thought they could use the Church of San Tommaso in Formis with the adjoining convent of the Trinitarian religious. Paul had first visited the Eternal City in the autumn of 1721 when, full of enthusiasm, he went to the Quirinal Palace, where the Pope then resided, to request approval for the Rule and the Institute of the "Poor of Jesus".

St. Vincent Strambi (+1824) was part of the community. He was in charge of organizing the student residence and for providing guidelines for the retreatants that began to arrive on the Caelian Hill. Various religious served as chaplains at the nearby hospital complex of “San Giovanni-Addolorata”. At that time, the area of the Celio was almost completely depopulated. The grounds were used for vegetable gardens, vineyards and pastures.

The traumatic event of the French occupation of the Papal States (1798) severely affected the Celio community. For several years, the retreat was completely abandoned.

Only with the return of Pope Pius VII in Rome and the re-establishment of the Papal States, was the community reconstituted as of 26 June 1814. This is a period of intense community and apostolic fervor.

The Congregation expanded beyond the Papal States and the Italian peninsula. The principal author of this activism was the Superior General, Father Antonio Testa (+ 1862). From the Celio hilltop, he governed the Congregation with a firm hand and clear-eyed vision.

The Passionists exercised their typical apostolic activity in the city and in the Roman countryside, even in areas infested by malaria. Many poor, who were assured bread and at times even a hot meal, flocked to the front door of the Retreat.

Another great trial for the community of the Celio occurred at the end of the existence of the Papal States and the capture of Rome by the army of Savoy (20 September 1870). Fortunately, the abolition of the community was averted because the retreat was reserved by the Vicariate of Rome as the retreat house for the Roman clergy. The Lateran Treaty (1929) reaffirmed this characteristic of the House on the Celio.

Among the most prominent personalities present on the Caelian Hill during the last decades of the nineteenth century, Blessed Bernard Silvestrelli (+ 1911) shines with special brightness. In the wake of his predecessor, Father Antonio Testa, he promoted the expansion of the Congregation while maintaining fidelity to the origins of the Institute.

Among other religious that graced the community during this period include the Venerable Fr. Nazareno Santolini (+ 1930), Fr. Norberto Cassinelli (+ 1911) and Fr. Germano Ruoppolo (+ 1909). Closer to our times, the Venerable Brother Gerardo Segarduy (+ 1962), the door keeper for many years at Sts. John and Paul, is an outstanding model of holiness and humble service.

Between the years 1930 and 1960 of the 20th century, it was necessary to enlarge various sectors of the Generalate building in order to enhance functionality.

Between the years 1950 and 1970 present on the Caelian Hill, among others, was the Superior General, the Servant of God, Fr. Theodore Foley (+ 1974).

Additionally there were great intellectuals such as Fr. Gerardo Sciatretta, Fr. Enrico Zoffoli, Fr. Paulino Alonso Blanco (+ 2007) and Fr. Fabiano Giorgini (+ 2008), as well as religious who served in the offices of the Holy See, including Fr. Ladislao Ravasi. Still today, the community of Saints John and Paul is a fixed reference point for all components of the Passionist Family.