His personality exerted great influence over history by making Hungary a Christian state.
Standing under the canopy of the peripteral high altar, with an apostolic cross and an orb as tokens of his apostolic authority as well as royal power in hand, the patron saint's figure cut in Carrara marble by Alajos Stróbl dominates over the impressive chancel.
The canopy is topped with the statue of Archangel Gabriel holding the Sacred Crown sent by Pope Sylvester II in the year of millenary. The back-wall of the chancel is adorned with scenes from the King's life on a series of bronze reliefs by Ede Mayer.
Above them you can read the supplication "King Saint Stephen intercede with the Eternal King of Centuries for us"
In the central space of the church, figures of Saints from the House of Árpád, first ruling dynasty in Hungary, can be found. The Our Lady altar of the nave is adorned with a painting by Gyula Benczúr, representing the historic event of St. Stephen offering his country to Virgin Mary, Our Lady, subsequent to the crown-prince's death. Prince Saint Imre, the King's only son is to be seen taking a vow of chastity in painting by György Vastagh the elder on the next altar where his Mother's, the Blessed Queen Gisela's bone relic is placed too.
A statue of Bishop St. Gellért (of Venetian descent) who died a martyr at the time of pagan revolt, is standing with his pupil St. Imre, already mentioned, cut in white marble by Alajos Stróbl in one of the niches under the dome.
In the great vaulted hall under the dome, a lyrical statue of St. Elizabeth of Thüringen, notable saint of charity in the Middle Ages, by Károly Senyei, is to be seen among saints of the Árpád dynasty.
A work of art by Béla Ohmann, representing the Dominican nun St. Margit, offered to God by her father King Béla IV at the time of the Mongol invasion in Hungary, is standing on the Our Lady altar.
The statue of King St. László of the Árpád dynasaty, endowed with knightly virtues while firmly establishing Christianity in Hungary, is the last work of art by János Fadrusz, an outstanding representative of Hungarian monumental sculpture.
The memory of St. Adalbert, patron saint of the Archdiocese Esztergom and the on-time Bishop of Prague who confirmed St. Stephen and was tenderly attached to the ruling family before dying a martyr in Prussia, has been immortalized in a painting by Ignác Roskovics at the entrance to the left aisle.
Frescoes originally planned were changed for mosaics on the dome and the ceiling. The bigger ones were finished by the firm Salviati of Venice while the smaller by the manufacture of Miksa Róth in Pest.
The half-dome of the chancel has been adorned with allegoric representations of parts of the Holy mass as designed by Gyula Benczúr while the mosaics of the high dome itself, symbolizing the heavenly spheres with the Creator God the Father in the middle, were designed by Károly Lotz. The series of mosaics portraying prophets and St. John the Baptist around the Christ enthroned refer to the connection between the Old Testament and the New One. Wall surfaces above the compound pillars supporting the dome are decorated with the figures of the four Evangelists. The biblical scenes of the Nativity, Jesus teaching, performing a miracle and His Resurrection, seen on the wide barrel vaults, were executed from plans by Károly Lotz, too.