The Greek Catholic population settled in the village in the first half of the 1700s. It is certain that the founder of the main branch at the time, Ferenc Kállay, like the neighbouring Kállay estates (Biri, Kiskálló), settled serfs from abroad on the Kállósemjén estate, which was short of labourers and had a significantly dwindling population, as early as the 1720s. As a result of the settlements, seventy Greek Catholic families lived in the village at that time, but by 1786 the number had risen to 660, and by 1806 it had fallen to 473.

The newcomers were also given the abandoned medieval church in the centre of the village, which, according to the 1747 census, had only its sanctuary.

The old building was gradually restored, but only part of it could be restored. It was rebuilt according to the Byzantine rite and consecrated in honour of the Archangel Saint Michael. On a visit to the church in 1780, the vicar noted that the sanctuary was spacious but dark and damp. The altar is made of stone and the iconostasis has a three-door door, with the bas-reliefs painted on wood panels and the other images on canvas. Next to the church was a four-spire tower built in 1765. At the time of the canonical visit in 1822, the church was described as being in good condition, but the roof and walls needed repair. Its iconostasis was found to be old, with cantor's benches and pews for the faithful along the wall.

In the first half of the 19th century, a high tower was planned to be built in front of the western façade, but this was not completed until later, and for a long time the bells were still in the tower next to the church.

In the first half of the 1800s, Greek Catholic shepherds who were skilled in shepherding and could also speak Hungarian were brought in by the Kállay landlords from the territory of the Bishopric of Oradea. And before the turn of the century, Hungarian-speaking smokers from the Great Plain and the northern counties settled here as a result of peasant migration.

In the 1770-80s, Romanian was still the 'fashionable language' in the village, due to the predominance of speakers; in 1803, three Greek Catholic students of the Marijapóc field town school in Kállósemjén still professed Romanian, and in 1806 the language of the liturgy was Romanian. From the 1810s, however, preaching and catechesis were conducted in Hungarian. The non-Hungarian-speaking Greek Catholics became Hungarianised. Some of them came from areas where they lived with Hungarians and understood their language. Most of them were mercenaries. The leadership of the village was in the hands of the serfs, and the wealthier ones were linguistically adapted to the more prestigious ones. In the 19th century, the Greek-Catholic population settled in the village, and there was already a significant proportion of Hungarian speakers.

Local registers have been kept in the parish since 1789. Until the 1810s, the pages of the first volume contain entries in Romanian in Cyrillic letters, proving that Romanian was the official liturgical language in the diocese. The registers of Kállósemjén tell of the presence of a mixed-language, diverse Hungarian-Romanian-Russian community.

By 1897 the new church was completed in eclectic style, with a wide nave and a high western tower. Only a part of the old sanctuary remains, the medieval origin of which is indicated by the polygonal buttresses and buttresses. The baldachin main altar was made in 1904 by the Rétay and Benedek Institute of Art and Industry in Budapest, and the complete new iconostasis was also commissioned from them. The vaults and side walls were painted by László Benke in 1960.

The parish was formerly part of the Greek Catholic diocese of Munkác. In 1912 it became a part of the diocese of Hajdúdorog, nowadays the district of the archdiocese of Mariánské Lázn? Elek Kriskó, Episcopal Councillor, served as a priest in Kállósemje for 52 years from 1918, in public honour. Before his arrival in Kállósemjén, Elek Kriskó served in the Greek Catholic Bishopric in Debrecen, where he was the sole survivor of the assassination attempt on Bishop István Dr. Miklóssy in February 1914, which claimed five lives. He opened the parcel that arrived in the bishop's name, and the deceptive covering letter about the valuable artefacts 'sent' in the parcel. However, the sender of the parcel had not placed any artefacts, but eighteen kilograms of explosives.

The Greek Catholic denomination is still the largest community in the municipality. In 1891 the population of the village was 2,166, of which 925 were Greek Catholics. In 1920, out of a population of 2903, 1357 were Greek Catholics. In 1942, the population was 2,124 out of 4,617. The church, which had been left over from the Reformed Church, was for a long time in a state of patchwork, until in 1896 the sanctuary of the medieval chapel of the Virgin Mary was incorporated into the new church, which still stands today. It was consecrated in honour of the Assumption.

The old high altar, still visible today, depicts the Assumption of the Virgin Mary, the patron saint of the church.

In 2013, the interior was partially restored, and during the archaeological excavation that preceded the work, the foundations of the medieval church, fragments of the vaulted ribs, a crypt and tombs were found, and the foundations of the original sacristy were also unearthed on the north side of the sanctuary. The traces of the excavated foundations were marked in the paving of the floor.

The members of the community, under the leadership of the deacon-parish priest István Árpád Orosz, carried out large-scale investments financed by various grants (TOP, ROHU) and their own resources, so that the church could worthily proclaim the glory of God inside and out.

The church roof and the tower have been renovated; the steeple cross and the globe have been coated with 24 carat storm gold. The tower clock was made of fire enamel, the walls were renovated inside and outside, taking into account the preservation of archaeological monuments; the niches on the exterior façade, previously unpainted, were decorated with the Archangels Gabor and Michael, and the icons are the work of the Transcarpathian icon painter Peter Bíró. New textiles and objects have also been added to the sanctuary and nave.