Santi Quaranta Martiri e San Pasquale Baylon, Rome

The Pontifical Institute of Arab and Islamic Studies (PISAI) traces the origins of its foundation back to 1926 and the work of the Missionaries of Africa (White Fathers) in Tunisia in a training centre for missionaries preparing to work in Muslim countries. In 1931 this foundation took the name Institut de Belles Lettres Arabes (IBLA). In 1949 it was decided to separate the teaching section from the other activities undertaken at IBLA which were more linked to the specifically Tunisian cultural scene. So a study centre was opened at Manouba (near Tunis) which welcomed students of Arabic language and Islamic sciences. Later, in accordance with a Decree of the Sacred Congregation for Seminaries and Universities dated 19 March 1960, this training institute was raised to the Pontifical Institute for Oriental Studies. In 1964, the Institute was transferred to Rome and its name changed to the Pontifical Institute for Arabic Studies thus avoiding any confusion with the already existing Pontifical Oriental Institute. In 1967, at the wish of Pope Paul VI, the Institute was situated in part of the Palazzo di S. Apollinare. The sole teaching language, other than Arabic, was French. In 1972 an English-speaking section was added. Italian was also adopted later. Since 1966, the Institute has had the faculty to award the Licentiate in Arabic and Islamic Studies at the end of a two-year course of study and preceded by a preparatory year. In accordance with Decree No. 292/80/5 of 25 May 1980, the Congregation for Catholic Education granted the Institute the authority to award the Doctorate. The name currently held by the Institute is the Pontifical Institute for Arabic and Islamic Studies (PISAI). Its new Statutes were approved by the Congregation for Catholic Education in Decree No. 826/79 on 13 September 2008.

San Callisto (English: Saint Callixtus, Latin: S. Calixti) is a Roman Catholic titular church in Rome, Italy, built over the site of Pope Callixtus I's martyrdom (c. AD 222). The original building dates from the time of Pope Gregory III (r. 731–741), who ordered the building of a church on the site. The church has been rebuilt twice since, first in the twelfth century, and the current church in 1610. In 1458 Callixtus III decreed it a titular church as a seat for Cardinals.Established in 1517, the Titulus San Calixti is currently held by Willem Jacobus Cardinal Eijk.

The church of San Cosimato is a church located in the city of Rome, Italy. It was originally built in the 10th century in the Trastevere rione and now includes the hospital known as "Nuovo Regina Margherita." Originally, it was built as a Benedictine monastery dedicated to Saints Cosmas and Damian, from whom it derives its name, and it carried the added designation of in mica aurea (“in the golden sand”) due to the presence of fluvial sand of yellowish color. The monastery was transferred from the jurisdiction of the Benedictine Order to that of the nuns known as the Recluses of Saint Damian (Recluse di san Damiano). From 1233, the church served as a hostel. Pope Sixtus IV had the church and monastery rebuilt in 1475, and after 1870, the convent was converted into a hospital. The façade of the church looks upon a public square that is also called San Cosimato. The church has a small Romanesque bell tower. The presbytery contains a fresco called Madonna and Child between Saints Francis and Claire, by Antonio del Massaro.

The Palazzo San Callisto (also known as the Palace of Saint Callixtus) is a Baroque palace in the Trastevere neighborhood of Rome and one of the extraterritorial Properties of the Holy See. The original Palazzo is located in the Piazza di Santa Maria in Trastevere, the later extensions have their entrance in Piazza di San Callisto. The entire complex is one of the areas of the Holy See regulated by the 1929 Lateran Treaty signed with the Kingdom of Italy. As such it has extraterritorial status. In the courtyard of the palace is the well where, according to tradition, Pope Callixtus I was martyred in the year 222.

The Fountain in Piazza Santa Maria in Trastevere is a fountain located in the square in front of the church of Santa Maria in Trastevere, Rome, Italy. It is believed to be the oldest fountain in Rome, dating back, according to some sources, to the 8th century. The present fountain is the work of Donato Bramante, with later additions by Gian Lorenzo Bernini and Carlo Fontana.

San Crisogono is a church in Rome (rione Trastevere) dedicated to the martyr Saint Chrysogonus. It was one of the tituli, the first parish churches of Rome, and was probably built in the 4th century under Pope Sylvester I (314–335), rebuilt in the 12th century by John of Crema, and again by Giovanni Battista Soria, funded by Scipione Borghese, in the early 17th century. The area beneath the sacristy was investigated by Fr. L. Manfredini and Fr. C. Piccolini in 1907. They found remains of the first church (see below). After they had made this discovery, the area was excavated and studied. The church is served by Trinitarians. Among the previous Cardinal Priests was Vincenzo Gioacchino Raffaele Luigi Pecci (1853–1878), elected Pope Leo XIII.

The Aqua Augusta was a short aqueduct in Rome. Owing to severe drought, the Emperor Augustus built the Aqua Augusta in or around 33 BC in order to supplement the Aqua Marcia, and then later the Aqua Claudia when required. However, the aqueduct was poorly designed and most of it collapsed in 27 BC.

In Ancient Rome, the Aqua Alsietina (sometimes called Aqua Augusta) was the earlier of the two western Roman aqueducts, erected sometime around 2BC, during the reign of emperor Augustus. It was the only water supply for the Transtiberine region, on the right bank of the river Tiber. This aqueduct acquired water mainly from a lake just north of Rome called Lacus Alsietinus (a small lake in southern Etruria, currently known as Lago di Martignano) and some from Lacus Sabatinus (Lago di Bracciano). The length of this mainly subterranean aqueduct was 22,172 paces (about 32.8 km) and had arches supporting 358 paces (about 0.53 km). Its water supply had a diameter of 392 quinariae (about 9 m). This water was not suitable for drinking, however, and emperor Augustus used it to fill his naumachia in Trastevere. This water supply allowed him and the public to enjoy sham naval battles. The water surplus was used for the irrigation of Caesar's horti (gardens) and for the irrigation of fields. Such an abundant supply of water gives an idea how much water Rome had at its disposal. In his chief work, De aquaeductu (written in 97 CE), containing a history and description of the water-supply of Rome, Sextus Julius Frontinus ascribes only a meager volume to the Aqua Alsietina. This makes sense, if the naumachia was no longer in use in his time (second half of the first century CE). Some traces of this aqueduct were discovered in 1720. An inscribed stone slab was found in 1887 near the Via Claudia. It is the only written record of the Aqua Alsietina. The fountain of the Acqua Paola in Rome, built under Pope Paul V announces wrongly on its triumphal arch that "Paul V restored the ancient ducts of the Aqua Alsietina". Actually the engineers had rebuilt the old Aqua Traiana, which had run close to the Aqua Alsietina.

The Basilica of Santa Maria in Trastevere (Italian: Basilica di Santa Maria in Trastevere); English: Our Lady in Trastevere) is a titular minor basilica in the Trastevere district of Rome, and one of the oldest churches of Rome. The basic floor plan and wall structure of the church date back to the 340s, and much of the structure to 1140–43. The first sanctuary was built in 221 and 227 by Pope Callixtus I and later completed by Pope Julius I. The church has large areas of important mosaics from the late 13th century by Pietro Cavallini.

Sant'Agata in Trastevere is one of the churches of Rome, located in the Trastevere district, at Largo San Giovanni de Matha, 91. The church is dedicated to the Sicilian St Agatha, martyred in approximately 251, whose cult soon spread well beyond Sicily. She is one of several virgin martyrs who are commemorated by name in the Canon of the Mass. Agatha is also depicted in the famous mosaics of the church of Sant'Apollinare Nuovo in Ravenna, where she appears, richly dressed, in the procession of women martyrs along the north wall.

San Francesco a Ripa is a church in Rome, Italy. It is dedicated to Francis of Assisi who once stayed at the adjacent convent. The term Ripa refers to the nearby riverbank of the Tiber.

Blessed Ludovica Albertoni (Italian: Beata Ludovica Albertoni) is a funerary monument by the Italian Baroque artist Gian Lorenzo Bernini. The Trastevere sculpture is located in the specially designed Altieri Chapel in the Church of San Francesco a Ripa in Rome, Italy. Bernini started the project in 1671, but his work on two other major works—The Tomb of Pope Alexander VII and the Altar of the Blessed Sacrament in St. Peter's Basilica—delayed his work on the funerary monument. Bernini completed the sculpture in 1674; it was installed by 31 August 1674.