Question: What kind of Christianity did the man who constructed the Basilica of St. John practice?

Context articles: Basilica of St. John the Baptist, Saarbrücken
Basilica of St. John the Baptist, Berlin
Justinian I
Basilica of St. John
Archbasilica of St. John Lateran
St. John's Regional Medical Center (California)
Oudenbosch Basilica
Basilica of St. Lawrence, Asheville
Cathedral Basilica of St. John the Apostle, Eger
Major basilica

The Basilica of St. John the Baptist (German: "Basilika St. Johannes der Täufer" ) also called Saarbrücken Basilica Is a catholic basilica located in the market of St. John ("St. Johannes") in Saarbrücken in Germany.
The Basilica of St. John the Baptist (German: "Basilika St. Johannes der Täufer Patron von Breslau" ) also called Basilica of St. John the Baptist Patron of Breslavia Is the Catholic cathedral seat of the Military Ordinariate in Germany.
 The church is located in the district of Neukölln in Berlin.
Justinian I ( ; Latin: "Flavius Petrus Sabbatius Iustinianus Augustus" ; Greek: Φλάβιος Πέτρος Σαββάτιος Ἰουστινιανός "Flávios Pétros Sabbátios Ioustinianós" ) ( 482 14 November 565), traditionally known as Justinian the Great and also Saint Justinian the Great in the Eastern Orthodox Church, was the Byzantine (East Roman) emperor from 527 to 565.
 During his reign, Justinian sought to revive the empire's greatness and reconquer the lost western half of the historical Roman Empire.
 Justinian's rule constitutes a distinct epoch in the history of the Later Roman empire, and his reign is marked by the ambitious but only partly realized "renovatio imperii", or "restoration of the Empire".
The Basilica of St. John was a basilica in Ephesus.
 It was constructed by Justinian I in the 6th century.
 It stands over the believed burial site of John the Apostle.
 It was modeled after the now lost Church of the Holy Apostles in Constantinople.
The Papal Archbasilica of St. John in Lateran (Italian: "Arcibasilica Papale di San Giovanni in Laterano" ), commonly known as St. John Lateran Archbasilica, St. John Lateran Basilica, St. John Lateran, or simply the Lateran Basilica, is the cathedral church of Rome, Italy and therefore houses the "cathedra", or ecclesiastical seat, of the Roman Pontiff (Pope).
St. John's Regional Medical Center is a hospital located in Oxnard, California in the United States, and is operated by Dignity Health, along with its sister hospital, St. John's Pleasant Valley Hospital in Camarillo, California.
 The hospital was founded in 1912.
 St. John's Regional Medical Center and St. John's Pleasant Valley Hospital offer comprehensive medical services, including 24-hour emergency medical and surgical services and care, cancer and oncology care and support, cardiovascular care, community outreach and screenings, diagnostic imaging services, laboratory services, maternity and women's services, neonatal intensive care, palliative care, patient and family education, rehabilitation services, spine and orthopedic care, weight loss surgery, wound healing and oxygen therapy, and more.
 Together, St. John's Regional Medical Center and St. John's Pleasant Valley Hospital represent the largest acute-care health organization in Ventura County.
 St. John's hospitals serve all of Ventura County and beyond, including the cities of Camarillo, Moorpark, Oxnard, Port Hueneme, Ventura, and Somis.
The Oudenbosch Basilica is a Roman Catholic basilica in the Dutch village of Oudenbosch.
 It was built under the initiative of father Willem Hellemons who was parish priest between 1842 and 1884.
 Its nave and interior were modeled after St. Peter's Basilica in Rome; while the facade is a replica of the Basilica of St. John Lateran also in Rome.
 The Basilica was designed by architect Dr. P. Cuypers.
 Construction began in 1865 but was not fully completed until 1892.
 The basilica is unique in the region in that it is quite large with classical Italian appearance that is atypical for most of northern Europe, let alone a small village in North Brabant.
The Minor Basilica of St. Lawrence the Deacon & Martyr is a minor basilica of the Roman Catholic Church in downtown Asheville, North Carolina, United States.
 The basilica was designed and built in 1905 by Spanish architect Rafael Guastavino along with his fellow architect R. S. Smith and the Roman Catholic community of Asheville.
 Pope St. John Paul II elevated the status of the basilica to minor basilica in 1993.
 It is on the National Register of Historic Places.
 It is the only basilica in western North Carolina.
 Its dome has a span of 58 by and is reputed to be the largest, freestanding, elliptical dome in North America.
 Except for the foundation and brick walls, the architectural style is Catalan, with the main example being the stairs behind the altar.
 It is located in the Downtown Asheville Historic District.
The Cathedral Basilica of St. John the Apostle or more formally Metropolitan Cathedral Basilica of St. John the Apostle and Evangelist, St. Michael and the Immaculate Conception (Hungarian: "Szent János apostol és evangélista o Szent János apostol és evangélista, Szent Mihály főangyal, Szeplőtelen Fogantatás főszékesegyház bazilika" ) also called Eger Cathedral is a religious building affiliated with the Catholic Church that functions as lacatedral of the Archdiocese of Eger, is located in the city of Eger, in the European country of Hungary.
Major basilica (Latin: "Basilica maior" ; plural: "Basilicae maiores") is the title given to the four highest-ranking Roman Catholic church buildings, all of which are also "Papal basilicas": the Archbasilica of St. John Lateran, St. Peter's Basilica, the Basilica of St. Paul Outside the Walls, and the Basilica di Santa Maria Maggiore.
 All of them are located within the diocese of Rome: St. Peter's Basilica is located in Vatican City and thus within the territory and sovereign jurisdiction of the Holy See.
 The other three are geographically located in Italian territory, but enjoy extraterritorial status under the Lateran Treaty.
 The Archbasilica of St. John in the Lateran is the seat of the Pope and the site of the Papal Cathedra, and is the oldest and first in rank of the major basilicas.