Pfarrkirche Unbefleckte Empfängnis Mariä

The parish church "Immaculate Conception of Mary" stands on historical ground. In its place was the command building (principia) of the Roman fort with the "flag sanctuary", the remains of which have been preserved under the church. In late Roman times, the flag sanctuary probably already served as a Christian place of worship. St. Florian suffered martyrdom in Lauriacum (Lorch a.d. Enns) in 304 AD. An old tradition of St. Florian worship in Zeiselmauer assumes that this was the birthplace of this first Christian martyr and saint on Austrian soil.

After the new settlement of the village by the Bavarians, a Carolingian hall church based on the remains of the Roman flag sanctuary was probably built before 900. It is one of the oldest church buildings in Lower Austria; its outer walls and the rectangular choir have been preserved in the lower church.

Zeiselmauer was a branch church of St. Andrä until 1400, a separate parish until 1568 and then a branch again. It only finally became an independent parish in 1784.
Alongside the tower, the high Gothic choir (2nd V. 14th century) is the oldest part of the building, with remarkable wall paintings from the beginning of the 15th century (north side God the Father with apostles and Mary, south side Archangel Michael with scales of the soul, painted in red chalk). In 1492, Emperor Frederick III donated a considerable sum for the late Gothic rebuilding of the nave. It was damaged in the Turkish War of 1683 and was given a Baroque barrel vault in 1684/86. The side chapel and sacristy were added at the same time, giving the parish church its present appearance.

The high baroque high altar (1740) was transferred here from the dissolved imperial convent in Tulln in 1810. It shows a crescent moon Madonna (1697) as the church's patron saint, as well as statues of St. Altmann and St. Anna. The baroque carved group "Crucifixion and Poor Souls" in the side chapel (mid-18th century) comes from the chapel of the Weinwartshof in Muckendorf. An oil painting with the rare motif "God the Father Pietà" (2nd half of the 18th century) is located above the doorway to the side chapel. The baptismal font dates from the year the parish was raised (1784). The altarpiece on the right side altar (M. Grassinger, 1796) with an apotheosis of St. Florian and the carved figure as the patron saint of fire on the sounding board of the pulpit are an expression of the Baroque veneration of St. Florian in Zeiselmauer.