The architectural development of the Basilica of Aquileia, dedicated to the Virgin Mary and the saints Hermagora and Fortunatus, started in the years immediately after 313 AD. In that period the Edict of Milan put an end to religious persecution and the Christian community was legally able to build its first place of public worship. In the following centuries, after the destruction of this first church, seat of a bishopric, the inhabitants of Aquileia built it up again other four times, using each time the structures of the previous buildings: Theodorian Hall, first half of the 4th century; Post-Theodorian North, middle of the 4th century; Post-Theodorian South, end of the 4th century or after the middle of the 5th century; hall of Maxentius, 9th century; Poppo's church, first half of the 11th century; rebuilding of the upper part of the church by Markward von Randeck, from the pointed arches to the roof, 14th-15th century.
The Basilica, as it is today, is in Romanesque-Gothic style. The inside is majestic and solemn and pervades us with a deep spirituality, which has grown along with the centuries. The entire floor is a wonderful coloured mosaic of the 4th century, brought to light in the years 1909-1912. The elegant hull-shaped timber roof dates back to the 15th century. This means that between floor and ceiling there are more than one thousand years of historical and artistic development. With its 760 square metres the floor is the largest Paleo-Christian mosaic of the western world. It alone could be enough to satisfy the traveller coming here to visit the Ecclesia Mater, which has become part of the world heritage. The mosaic was partly damaged due to the construction of the columns flanking the right side at the end of the 4th century according to some scholars and after the middle of the 5th century according to others. It is also possible to see the foundations of the columns because at the beginning of the 20th century the medieval white and red tiled floor made under Patriarch Poppo (1031) was removed in order to uncover the precious Paleo-Christian mosaic. The glass platforms are situated at the level of the medieval floor.
Entering the Basilica we can see the mosaic floor belonging to the Theodorian South Hall, one of the three main rooms constituting the bishop's seat during the empire of Constantine. Theodore, whom the inscription on the floor in the Fishing Scene refers to, had built a complex of worship perfectly corresponding to the liturgical needs of that time. He bought an urban area, demolished the warehouses situated in it and built a complex with the shape of a horseshoe. Two rectangular parallel halls (South and North Hall), connected by a rectangular transversal hall. Between the two parallel halls to the east of the transversal hall there were the baptistery, some ancillary rooms and the entrance to the whole complex. Of this first complex are visible today: in the Basilica. the mosaic of the South Hall, part of the cocciopesto floor of the transversal hall, part of the mosaic floor of the entry; in the Crypt of Excavations, remains of the mosaics of the North Hall, remains of the cocciopesto of the transversal room and the floors of the ancillary rooms; the remains of the old baptistery with circular baptismal font are not visible instead. According to some scholars the South Hall was used by catechumens preparing for baptism, while the North Hall was used for the Holy Mass. Other scholars instead are convinced of the contrary. The connecting room was used both as a dressing room before the baptism following the rite of immersion and for the celebration of the Confirmation. The mosaic floor is divided into panels bordered by vegetal motives (acanthus shoots). There are ten "carpets", each representing different highly symbolical scenes, some of which are considered particularly important.
Walking along the platform we can admire the first scene: the Battle between Cock and Tortoise. The cock is the symbol of the light of a new day, thus representing Christ, the "light of the world". The tortoise, whose Greek name means "dweller of the darkness", is instead the symbol of the Evil. Passing on to the right we can see the scene of the Good Shepherd with the Mystic Flock. Christ is portrayed as a beardless young man bearing the lost lamb upon his shoulders. In one hand he holds the syrinx (the shepherds' flute), symbol of the gentleness he takes care of his flock with. He is surrounded by land, sky and sea animals, because his flock is composed of all men "of good will", of whatever race and culture. In the clipeus we see several portraits of benefactors (a man wearing a toga, a veiled woman and girls). In the other round frames there are the images of the seasons (Summer and Autumn; Winter and Spring have been destroyed by the foundations of the columns) and of the acrostic fish ICHTYS ("ichtys" is the Greek name for "fish"; each single letter is the initial letter of the words "Iesus Christòs Theu Yòs Sotér", meaning "Jesus Christ Son of God the Saviour"). Close to the carpet with the portraits we can see the images of the donors and of the Christian Victory. The classic winged Victory bearing a laurel crown and the palm branch for the winner has been transformed into the Christian Victory donating the Eucharist to the believer winning the battle against the sins. The magnificent Fishing scene is a work of the Sea Master and describes the preaching of the Apostles ("Follow me and I will make you fishers of men": Matthew 4,19). The fishes represent the people listening to the good news, the boat is the symbol of the church, the net (but also the fishing-line) represents the kingdom of heaven ("The kingdom of heaven is like a big net that was cast into the sea…": Matthew 13,47). In the great fishing scene we can admire the three episodes concerning Jonas and representing the allegorical announcement of death, resurrection and ascent to heaven of Christ: Jonas swallowed by the sea monster, Jonas thrown up by the monster, Jonas resting under the pumpkin tree
The architectonic structure dates back to the 9th century, while the beautiful frescoes were painted in the second half of the 12th century. On the vault there are 19 scenes narrating the History of Hermagora and the origins of Christianity in Aquileia In the four lunettes there are displayed the scenes of the Passion of Christ and the Death of Mary
The apsidal frescoes date back to the first half of the 11th century . On the sides of the Enthroned Mary portrayed inside the mandorla there are the Martyrs of the Aquileian tradition: on the right Hermagora, Fortunatus and Euphemia, representing the group of the Four Virgins of Aquileia, and on the left Mark the Evangelist, Hilary andTatianus
On the column at the corner there is the bust of the Christ of the Trenches, impressive and moving sculpture made by Edmondo Furlan, a sculptor who was also a soldier during the First World War.
The monument dating back to the 11th century is the reproduction of the Anastasis Church (of Resurrection), built in ancient times in Jerusalem on Christ's Sepulchre. Originally it was used during the ceremonies of the Holy Week.
The Crypt of Excavations is an underground archaeological area situated underneath the garden surrounding the bell-tower, where we can see archaeological remains of three different periods. Following the suggested route on the platform level we can see the cocciopesto belonging to the floor of the Theodorian transversal hall (beginning of the 4th century). At a lower level we see the mosaics of a domus, a Roman house, dating back to the times of Emperor Augustus (end 1st century BC -beginning 1st century AD). On a higher level there are parts of the mosaic and the foundations of the columns of the Post-Theodorian North (middle 4th century) destroyed by Attila in the year 452. Not immediately clear to understand are the remains of the warehouses dating back to the 3rd century, erected some time after the domus, and probably used until the works made byTheodore. Crossing the old threshold, we enter the TheodorianNorth Hall, where we can admire wonderful mosaics representing various animals (especially birds, but also the hippogryph) in strange positions (the lobster on a tree) or with particular objects (a goat with a horn and the pastoral) and rich of symbolic meanings referring to the truths of faith, the Christian virtues and eternal life in Paradise. Going all around the foundations of the bell-tower it is possible to admire other mosaics (the ram, the battle between cock and tortoise, the rabbit, the star of David) and the remains of the baptismal font of the second baptistery (of the Post-Theodorian North).
The baptistery, which was the third of its kind in Aquileia, is the result of various changes and rearrangements. When it was built under Bishop Chromatius ( 4th century), it featured a square floor plan. Later this floor plan was replaced by an octagonal one in order to recall the eight day: the Resurrection. In the middle of the baptistery is a six-sided font, the result of a 19Th century restoration. It is surrounded by six columns, which once supported a shallow cover as well as the ambulatory up to the side walls.
The Chromatian mosaic, even though it has the same geometrical structure of the Theodorian mosaics, has a poorer and smaller decorative patterns. The middle decorations have important meanings but more stylized and not si realistic. Geometrical moduls can be found in the outer parts, whereas six lambs ( or sheep) are portraied into six hexagons. On the western wall, one can see the beautiful mosaic of the peacock, found on the floor of the corridor connecting the Basilica and the Chromatius Hall.
The imposing Campanile of Aquileia, which rises alongside the patriarchal Basilica, was built in the first half of the 11th century under Patriarch Poppo; later, it was enhanced ( during the 14th cent. ) until 73 m. The visit to the bell-tower , allows a person to the “panorama” (that goes from the alps, to the karst & the Adriatic sea) and also to visit the Theodorian mosaic that was part of the ancient north hall.