In the mid-18th century, the interior of the Latin Cathedral in Lviv was modernised. At that time, the old, decayed main altar was moved to the line of the rainbow arch. A new altar was built in the presbytery of the sanctuary based on a design by Piotr Polejowski, together with a niche for the miraculous image of the Mother of God of Domagalicz.

Great modernisation of the Latin Cathedral
In 1760, the archbishopric of Lwow was assumed by Wenceslas Hieronim Sierakowski (1700-1780), Bishop of Przemyśl. He was famous for his love of art, and was an accomplished collector and fund-raiser. As the new head of the archdiocese, he decided to modernise the Lvov Cathedral Church. The medieval building had been neglected, filled at the time with numerous objects, including altars, epitaphs, plaques, pews and friar's chests from various eras, and was in need of tidying up. Archbishop Sierakowski employed the Lvov architect Piotr Polejowski (1734-1776), a pupil of the architect Bernard Meretyn (d. 1759) and the sculptor Johann Georg Pinsel (d. 1761/1762), to prepare a project for the modernisation of the church, including both the exterior architecture and the interior decoration and furnishings.

Work on the cathedral, which lasted fifteen years, began in 1765 with the tidying up of the presbytery. Among other things, the old and decayed main altar was dismantled and moved to the line of the rainbow arch, and the miraculous painting of Our Lady of Domagalicz, by Josef Szolc-Wolfowicz (died 1626 or 1627), which had been there for some time, was temporarily placed in the Wisniowiecki Chapel.

New main altar - general view
The foundation stone of the new main altar, designed by Piotr Polejowski, was laid on 7 May 1766. The masonry setting was built of brick finished with coloured stucco imitating greyish-blue veined marble. It consists of a central section, founded on the curve of a concave ellipse, articulated with columns and two bundles of columns on pedestals set diagonally at the corners of the altar, which create an optical whole and deepen the elliptical projection. The dynamic structure is further emphasised by the wavy sections of the beam above the columns and the slender, openwork finial with a window incorporated into the composition.

When designing the new settee, Piotr Polejowski drew on the experience gained in Bernard Meretyn's workshop and referred to altars designed by him, including those in the church in Horodenka and Monasterzyska, as well as to the form of the tabernacle that Meretyn created for the church in Hodovica. The main altar of the Lviv Cathedral is the most magnificent work created by Lviv sculptors in the second half of the 18th century that we can still admire today.

New main altar - sculptural decoration
. The sculptural decoration of the altar was created in 1766-1770 by Peter's brother, Maciej Polejowski (died after 1794). The artist created four supernaturally large statues of the Church Fathers: St Augustine, St Athanasius, St Ambrose and St Jerome, set in the main part of the altar. This was the first large-scale commission carried out by Maciej Polejowski on his own, as he had previously worked with his brother in the family workshop on the main altar in Navarra, near Lwów.

Polejowski's work also includes two large figures of angels seated in dynamic poses and with wings spread wide on wavy abutments at the top of the altar, and numerous putti. The work on the decoration of the finial was assisted by the sculptor Jan Obrocki, who made a woodcarving radial gloria with the monogram MARIA in the altar finial in 1768-1770. The gilding of the decorative elements was done by Mathias Müller, a painter and gilder from Lvov, who specialised in this field.

. The sculptures of the Fathers of the Church by Maciej Polejowski are among the best works of the so-called Lvov rococo sculpture, created in the second half of the 18th century, and Maciej himself is widely regarded as the most important representative of the second generation of Lvov rococo sculptors.

The central part of the altarpiece, following a long tradition, is covered with a moving image. The first veil depicting the Assumption of the Blessed Virgin Mary was painted in 1769 by the Lvov painter Marcin Stroiński (Stanislaus' brother), but it did not gain the approval of Archbishop Sierakowski, who commissioned his court painter, the Italian Antonio Tavelli (d. after 1778), to paint a new picture. The artist fulfilled the commission only in 1778, and from then on, the painting "Assumption of the Blessed Virgin Mary" is located in the main altar. Tavelli is also known for other works for Archbishop Waclaw Hieronim Sierakowski, and as the author of the polychrome of the church in Navarre.

The consecration of the renovated cathedral took place on 23 April 1776.

. Miraculous image of Our Lady of Domagalicz
. In the main field of the altar in the Latin Cathedral, Piotr Polejowski designed a niche ending in a basket arch (flattened), intended for the miraculous image of Our Lady of Domagaliczov. In order to properly display the universally venerated image, goldsmith Jozef Lukaszewicz made a silver pedestal made of volutes (spiral elements), surrounded by seven silver columns on slender pedestals, crowned with wavy pediments on the beams and putti with flame vases. The column directly behind the painting has been given an elaborate silver radial gloria, supported by a rococo vase bearing clouds, winged angel heads, a silver gilt crescent and a sceptre of the same kind.

The whole structure, in the centre of which the image was inserted, referred to the temple of Solomon and was a symbol of the Divine Wisdom, identified with the Lviv Cathedral. In connection with the planned coronation of the miraculous image with papal crowns (celebrated on 11 May 1776), in 1773-1776 the Lviv jeweller and goldsmith Pierre Chalier made a silver dress for the image, gilded and set with precious stones.

Despite further transformations in later times, such as the addition of a new antependium at the turn of the 19th and 20th centuries, the insertion of a post-conciliar altar and pulpit, and the replacement of altar candlesticks, we can still admire the mastery of the design and craftsmanship of the main altar by the most important artists of Lviv in the second half of the 18th century.

The main altar in the Latin Cathedral - now
. The altarpiece is preserved in very good condition, thanks to numerous restorations carried out since the 19th century. The last major conservation took place in 2008 and was carried out by Polish conservators under the supervision and with the funds of the Ministry of Culture and National Heritage and the Senate of the Republic of Poland. At that time, the work included the complete conservation of the structure, sculptural and ornamental decoration. The cleaning of the elements, restoration of the original colours and gilding were carried out by a team of conservators under the direction of Jan Wiłkojec. Slightly earlier, in 1996, Anna Kostecka conducted the conservation of the miraculous painting of the 'Mother of God of Domagaliczov', and in 2005 Ewa Wiłkojć and Justyna Wyszkowska-Baścik conserved the Tavelli painting on a slider with the Assumption of the Blessed Virgin Mary. The final stage of the extensive work was the conservation of a 19th-century embroidered antependium carried out in 2009 by Marianna Kwiatkowska from Lviv.