Cappella dei Missionari di Mariannhill is a later 20th century convent chapel at Via San Giovanni Eudes 91 in the Gianicolense suburban district.
The founder was the Austrian Franz Pfanner, who became a Trappist monk of Mariawald Abbey (now defunct) in Germany in 1863. He had served as a diocesan parish priest and army chaplain beforehand, and had good contacts at Rome. In 1866, exploiting these connections, he helped to obtain the ancient monastery of Santi Vincenzo e Anastasio alle Tre Fontane for the Trappists.
In 1882, in response to an appeal, he personally oversaw the foundation of a monastery at what is now Mariannhill ("The hill of SS Mary and Anne") near Durban in South Africa. This was in imitation of the situation in western Europe in the early Middle Ages, when monasteries were often founded in areas with no organised Church presence and where they could act as foci for developing Church life.
However, modern missionary demands were not compatible with the Trappist rule, especially as regards the running of schools and having monks leaving the monastic enclosure to go on missionary tours. Both of these were especially problematic when they involved contact with women and girls, so in 1885 Fr Pfanner founded the "Missionary Sisters of the Precious Blood" for the purpose. This was in the same year that Mariannhill became an abbey, and Fr Pfanner was elected as the first abbot. He served until 1894, overseeing a massive growth in missionary activity and the size of the community.
The wider problems as regards Trappist monks teaching in schools and residing in mission out-stations remained, but Fr Pfanner tried to reconcile the full rigour of the Trappist rule with these demands. Unfortunately, some of his innovations were not acceptable to his Order and he had to resign in 1893.
Mariannhill Abbey had to wait until 1909 before it received papal permission to become the mother-house of a new missionary congregation, with a rule of life adjusted to circumstances rather than one wedded to Trappist observances. This amounted to the formal foundation of the Mariannhill Order, to which the Missionary Sisters were regarded as belonging.
The Order has become international, with a list of countries here.
In 1964, a project was entered into to build a new Generalate in Rome -the Order's first convent in Italy. The intention was for both male and female branches to share the complex. The work was completed in 1968, the architect being Silvio Galizia.
In 2015, the Missionary Sisters decided to move out and leave the complex to the men. They did not go far, but only to number 95 in the same street. They seem now to be sharing the premises of the Generalate of the Scheut Missionaries -although the Diocese does not list them as being resident in Roma at all (2018).
Galizio is well-known for using odd and unusual forms in designing his buildings, and this convent is no exception.
The complex is set in a parkland setting, up a long drive. It is formed of a series of two-storey ranges joined end-to-end to form a curvaceous Y on the plan. The chapel occupies the centre of the stem of the Y.
The chapel's plan is a very irregular hexagon, with five external angles and one internal one. Basically, it is a trapezoid with two side walls diverging from the front, the right hand one at a greater angle and the left hand one at a very slight angle. The back of the trapezoid is at a substantial angle to the front, running back from the left hand side. However, this line has an incut step in it in the plan - the left hand back side of the edifice has a wall running parallel to the front from the far left hand corner, and a short wall running back from the single internal angle to join the far wall of the sanctuary running off to the right at the substantial angle aforementioned.
The single internal angle is the only right angle in the entire edifice.
The façade has a shallow lobby with a frontage at an angle to it, and a flat canopy roof which is almost a thin right angle in the plan. This lobby seems to double up as a communication corridor between the convent ranges on either side of the chapel.
The left hand side wall abuts the convent on that side. The right hand side wall is mostly exposed, and is in completely blank dull pink render. The two walls flanking the internal angle protrude above the convent range abutting them. The back wall of the sanctuary has a very obtuse internal angle in its left hand side, followed by two shallow vertical steps before it ends at a wide window strip abutting the far right hand side angle.
The roof is "sort-of" flat, but is both slightly curved and slightly pitched. It is in a grey composition.