It is an exceptional place, primarily due to the figure of its founder. It does not happen very frequently that an institution of culture is founded by a saint. The Przemyśl bishop Józef Sebastian Pelczar, as early as at the beginning of his pastoral service, appealed for taking care of the testimonies of people's religiosity and in 1902, at the Archdiocesan Synod in 1902, established the diocesan museum. In connection with that, works of religious art from the Przemyśl diocese at that time began to be collected. The collection was housed in the former Jesuit oratory, above the nave of the 17th-century church of the Sacred Heart of Jesus. The opening celebration of the museum took place after six years of collecting and arranging the place, in 1908.
The museum existed in an unchanged form and in the same place for more than one hundred years. However, due to the bad technical state of the seat, it was decided to move the Museum to the new premises. Due to the efforts of people fond of the Museum, as well as the determination of guardians of the collection, conservation of some of the works of art began. Archbishop Józef Michalik designated two historical buildings neighbouring the Cathedral of John the Baptist for the new seat of the Museum. The opening celebration for the "new Museum" took place on one hundredth anniversary of designation of the first seat, on 27 August 2008.
The pearls in the collection of the Museum are Polish medieval works, giving a wide overview of the era due to examples from all sections of art. Among the displayed panel paintings, most often parts of altars, it is worth mentioning the outer panels of the triptych from Załęże (around 1470), presenting the Annunciation scene, or the triptych from Osiek Jasielski, illustrating the activity of Apostles Peter and Paul (1527). A new exhibit in the collection is a renovated painting of the Mother of God with Infant of the Lesser Poland Hodegetria type. Exceptional, from the iconographic point of view, is the example of the so-called Holy Family the Greater, presented on the predella from Jaćmierz. The sculpture shows the presentations of the Mother of God with Infant, the so-called Beautiful Madonnas, among others: from Bączał Dolny (end of 15th century) or Święcany (about 1375). An important monument comprises of figures reconstructing the layout from the so-called rood beam, among which the monumental crucifix from Nowe Miasto draws the visitors' attention. Although it is not in the typical canon of beauty, it strongly appeals with the emotional load.
A collection of medieval textiles is worth mentioning. The oldest exhibits, dating back to the 14th century, are the two parts of chasubles. Later embroideries come from the second half of the 15th century. Among them there are chasuble embroideries with a scene of the Dormition of the Mother of God among the apostles (analogues to embroideries made in the Cracow centre) and with a scene of the suffering of Jesus on the cross, called "arbor vitae". In the new wing of the museum one can also see copes and chasubles, among which particular attention should be drawn to the textiles gained during the Battle of Vienna in 1683.
The Baroque era is represented by a collection of portraits. Some interesting examples from this group include a portrait of the Przemyśl bishop Paweł Piasecki (1644-1649), author of the "Polish Chronicle", as well as a large portrait of the Przemyśl bishop Aleksander Antoni Fredro (1724-1734).
The collection includes the paintings of a French artist, Augustyn Mirys, the painter of the Branicki family from Białystok. Apart from the image of Jan Klemens, there is a portrait of his wife Izabela Branicka nee Poniatowska, as well as of their relative, Urszula Lubomirska nee Branicka. An attractive example of the Polish group portrait is the painting presenting the Krasicki family from Dubiecko, painted by Mikołaj Tereinski (around 1753).
The collection of the Museum also includes Sarmatian coffin portraits and numerous examples of religious paintings from the 15th to the 19th century.
It is also possible to enter the 17th-century gentry room. This new attraction of the Museum was moved here from the so-called Orzechowski Manor House, neighbouring the Cathedral. In the seat Stanisław Orzechowski, the canon of the Przemyśl chapter, one can see original equipment from the 17th century as well as parts of religious polychrome.
In 2011, a new exhibition wing was opened with the exhibits which used to be parts of the church equipment, made in the tradition preceding the Second Vatican Council. In the main hall one can feel like in an old church with a traditional altarpiece, sculptures of saints and a collection of liturgical vessels (chalices, monstrances, candlesticks etc.). A collection of icons is exhibited in one of the rooms, among which the icon presenting the Dormition of the Mother of God and Mother of God with prophets are particularly interesting, dating back to 16th and 17th century.
Other interesting exhibits include the sculptures of Thomas Hutter, the famous Baroque artist from the Lvov school or tapestries brought from the pope's manufacture of San Michele by the bishop Aleksander A. Fredro (1724-1734). They were made following the designs of Guido Reni (1575-1642) and present the figures of four Evangelists (they were unsuccessfully looked for by the Germans during the occupation).
In the three rooms, on the ground floor of the so-called Psałterzówka there is a collection of items connected with the blessed Pope John Paul II. One can see here both personal items used by the Pope (papel garments, his backpack and a mat which he used during his hikes) as well as many objects which he gave to the museum.The Archdiocese Museum, founded in 1902, is located in historical, 16th- and 17th-century buildings in the Cathedral square. This is the oldest museum in the south-east of Poland, with works of art from the Middle Ages, Baroque and other periods. There is also a collection of items associated with the Holy Father John Paul II.