Depicted are: the birth of Gertrude, the taking of the vows, a bishop consecrating Nivelles Abbey, Gertrude saving a house on fire, and Gertrude saving a ship in a storm. The mural on the west wall shows "Saint Gertrude's love drink" ("Sint-Geerteminnedronk"), the ancient custom to drink to a healthy homecoming of someone who is undertaking a long journey. Saint Gertrude is the patron saint of travellers. Both the architectural sculpture in the church and the sculptural fragments that were recovered in 1913 from underneath the church floor, testify of a rich artistic tradition. The massive late-Gothic capitals that adorn the composite columns between the nave and the north aisle, are impressive both in size and skill. The ribvaults are decorated with sculpted keystones and corbels. Beautifully detailed are the four corbels with the evangelists' symbols. Two Baroque altars have been preserved in the south chapels. They are of local limestone with stucco decorations in Louis Quatorze style. Two interesting reliefs decorate the north and south wall of the choir. The smaller one on the north wall depicts a heart that is pierced by a sword with two hands folded in prayer below. Inside the heart the letters IHS (Jesus) and MA (Mary) have been carved; above it the date 1595. This might be an epitaph that was removed from elsewhere. The larger relief on the opposite wall consists of four vertically arranged parts, partly damaged by a 19th-century mezzanine floor. It probably refers to a "Vidimus" (Latin: "we have seen") of 1482, in which the dean of St. Servatius confirmed a privilege of Pope John XXII of 1318, allowing the Crosiers to celebrate mass, collect money, etc. The papal tiara and Saint Peter's Keys of Heaven are clearly recognizable. Above and below are depictions of the coat of arms of the Crosiers and what looks like a sundial or an astrological chart. These may not be related to the central reliefs. The bottom drawing may be connected to prior Mathias Mijnecom who was known as "Astronomas" because of his knowledge of mathematics and astronomy. Around ten ledger stones remain in the church, all of laypersons. For the burghers of Maastricht the Crosier Church obviously was a popular place to be buried.