The Chapel of San Nicolás is a Romanesque temple dating from the 12th century. It is located next to the church of the monastery of San Pedro de Galligans.

Its existence is documented in the year 1134. Its construction is somewhat later than that of San Pedro de Galligans, although its lower part seems to date from a somewhat earlier period and may have been part of a small church built there previously. There was an early medieval cemetery on this site, so it may have been a funerary chapel built from a monumental tomb.

Later, the chapel was linked to the monastery cemetery and served as a parish church in the San Pedro district of Girona.

It was originally a square, central building with four semicircular apses and covered with an octagonal dome on trumpets. Later, perhaps in the 13th century, the western apse was removed and replaced by a nave covered with a barrel vault, as we know it today. There are other churches from the same period and with similar characteristics, such as the Chapel of the Holy Cross in Montmajor, in Arles.

According to Joaquín Pla Cargol, the outer buttresses of the nave probably date from the 15th century.

It was the guild chapel of the tanners, who worked in this lower part of the town on the banks of the river Galligans. In 1515 the guild renovated the chapel with an altarpiece commissioned from the Girona cabinetmaker Bernat Albar.

Until the beginning of the 19th century, the chapel of Sant Nicolau was used for worship by the inhabitants of the village of Sant Pere, reserving the monastery church for community functions. However, baptisms, marriages and funerals were usually celebrated in Sant Pere, which for centuries had the status of a parish church. Villanueva records in his Viaje Literario that the church of San Nicolás was built within the cemetery of the abbey of San Pedro. In volume XLV of La España Sagrada it is stated that after the War of Independence the Sacraments came out of it, which proves that it functioned as a church until 1835, the year of the Disentailment.

In 1840, after the Disentailment and the corresponding auction by the State Administration, it was bought by a private individual to be used as a timber warehouse. It passed through various owners, maintaining its use as a warehouse and sawmill, until 1942, when the property was transferred to the City Council of Girona.

It was declared an architectural-artistic monument by Royal Order of 15 March 1919 by the Ministry of Public Instruction and Fine Arts.

The restoration of the chapel began in 1940, directed by the architect Alejandro Ferrant. During the works, the building collapsed and the chapel was restored for worship, which continued until 1980.

In the years 1975 to 1977 new archaeological excavations were carried out which confirmed that the chapel originally had a circular floor plan.

The building has a barrel-vaulted nave and a three-lobed apse. Its dimensions are: length 29.2 m; width at the crossing 8.6 m; height of the vault 7 m and height of the vault at the crossing 9.5 m. The vault of the nave is partly made of volcanic stone, which is very porous and light in weight, in order to reduce its weight. The west end of the nave has no exterior door or any trace of a façade, probably due to its demolition when the Clerics' Hospital was built almost next to it.

During the restoration work carried out in 1944, a small volume was attached to the western façade, which was used as a sacristy. The door opened in 1763 on the southern façade, which was moved from its original position, was placed in this addition. Its lintel shows a crowned lion representing the tanners' guild.

The dome is decorated with blind arches, as in the case of the apse, typical of the 12th century. With the exception of the dome, the work is made of small, regular ashlars, which gives it a certain archaic character.

The interior is currently devoid of ornamentation and is used as a cultural space for exhibitions, the most important of which is held every year in the first fortnight of May under the name of "Girona tiempo de flores" (Girona, time of flowers).