The first mentions of the Franciscan monastery come from 1285. Bishop Herman von Cammin granted an indulgence for those visiting Franciscan monastery churches. It also included the monastery church in Namysłów. That same year it was reported that 8 out of 12 Convents of Friars Minor moved from the Polish to the Saxon religious province, including Namysłów. The construction of the temple was probably initiated at the end of the 13th or the beginning of the 14th century.

In 1321 the monastery was already mentioned as the Convent of the Blessed Virgin Mary. During the first stage, a small church was built (the present-day chancel), and the nave was built later, in the 15th century.

In 1420, a monastery was already built next to the existing church.

After being taken over by Protestants (from 1536), the monastery was used as a hospital and warehouse. The temple gradually fell into ruin.

After an inspection in 1666, it was determined that the so-called "Polish" church had a damaged ceiling and was generally in poor condition.

Only in 1675, after many years of efforts by the Franciscans, thanks to the decision of Emperor Leopold I the Church of the Assumption of the Blessed Virgin Mary and the monastery buildings returned to their previous owners, namely to the Reformed Brothers of the Czech Province. The monastery was named after St. Peter of Alcantara.

Since 1678, the monastery has been inhabited by 12 brothers and, as Fr. Bernard Sannig described it in his chronicle: they live simple lives, maintain themselves by daily, uncertain begging.

In 1716, after the church was renovated, it has been re-consecrated, and included 8 baroque altars.

On November 10, 1810, the Franciscan order was dissolved. That way the state took over the buildings and goods belonging to the Franciscans. The state thus took over the buildings and goods belonging to the Franciscans. At the time of the dissolution, Fr.Christian was the guardian with 10 presbyters and 13 brothers.

The last mass was probably held on May 2, 1812. Part of the furnishings was sold, and the remainder was given to the parish church. To this day, the church of St. Apostles Peter and Paul in Namysłów include altars of: St. Peter of Alcantara, St. Anthony, St. Francis, and the Holy Cross, as well as the Stations of the Cross taken from the Franciscan church. The altar of the Fourteen Helpers was moved to Bogacica near Kluczbork. The marble floor of the church was torn off in 1812 and handed over to the Evangelical church in 1814.

In 1825 the city council bought the church building, and after renovation it was turned into amber warehouse.

In 1980, the idea of reclaiming this ancient temple was born.

As a result of undertaken actions, at the request of the Parish of St. Apostles Peter and Paul in Namysłów of August 18, 1982, the Ministry of Culture and Art handed over the historic post-Franciscan church for the parish's perpetual use on September 30 of that same year. Renovation works began from that moment.

On November 11, 1988, on the 70th Anniversary of Regaining Independence, the church adapted to liturgy was solemnly consecrated by His Eminence, Father Cardinal Henryk Gulbinowicz, Metropolitan Archbishop of Wrocław.

On June 27, 1992, Fr. Card. erected by the church a diocesan parish of St. Francis of Assisi and St. Peter of Alcantara. The invocation of these saints refers precisely to the temple’s Franciscan history.

On December 29, 1992, the newly established parish received the ownership of the monastery buildings adjacent to the church, which have been converted into a parish office, parsonage, and vicar's office for priests.