THE FORTIFIED CHURCH OF AITA MARE AND THE SURROUNDING DEFENSIVE WALLS
Archaeological research inside the church building has revealed the remains of an earlier, polygonal apse with buttresses, which was built in the mid-14th century at the earliest. The dating of the wooden elements indicates that the timbers in the northern and south walls of the nave were felled in 1435.
The major construction work on the church dates from around the turn of the 15th and 16th centuries (the reused timber in the roof structure was originally harvested around 1503-1504). This is the period when the apse, flanked with buttresses and having the same width as the nave was built, as well as the sacristy, and the openings resembling embrasures. Around 1512 the wooden ceiling of the nave was replaced by rib vaulting with terracotta ribs starting from corbels decorated with rings. At this period the richly profiled stone frame of the sacristy door in the northern wall of the sanctuary was completed and the Gothic lancet windows were decorated with tracery.
At the time of the Protestant Reformation, the Catholic liturgical space was completely transformed: the altars were removed, the wall paintings were whitewashed and later plastered over, the sacristy was dismantled and pews were placed in the sanctuary, shifting the liturgical center to the axis of the pulpit and the Communion table.
The tower attached to the west wall was built most probably in the late Gothic period but it was rebuilt later, at the end of the 18th century. This collapsed into the nave during the devastating earthquake of 26 October 1802, which tore the vaulting of the nave, destroyed the western gallery and crushed the pews.
The newly erected tower incorporated the original stonework, the stone frame of the western entrance and elements of the western stone gallery – many of which can still be seen in the wall fabric of the tower. The brick ribs of the former vault were incorporated into the northern wall of the external staircase leading to the western gallery. Today, the rebuilt vault of the nave only mimics the former brick ribs.
Another earthquake in 1838 damaged the tower again. Repairs in 1879 caused extensive damage to the frescoes and the fine stone detail of the Gothic windows were broken out. In 1897, the tower deck was struck by lightning. In 1944, during the fighting on the site, the southern façade of the tower was hit. The last earthquake causing significant damage occurred in 1977.
The building was completely renovated between 2019 and 2021.
During the late Gothic construction works of the 15th-16th century the church was significantly enlarged and surrounded by an oval-shaped stone defensive wall. At the turn of the 16th and 17th centuries, the Unitarian Church of Aita Mare was enclosed by an even more robust and modern defense system, with towers. The construction of the parallelogrammatic shaped wall reinforced with bastions was started in the early 1620s and completed by the 1650s after several modifications.
The towers imitate the Old Italian bastions common in military architecture of the period. Their masonry is not interwoven with the ramparts, therefore it is quite clear that they were built later than these. The timber used at the entrance to the gate tower was cut in the winter of 1637/1638. The construction of the other two, diagonally placed towers was still in progress in the second half of the 1640s. Interestingly, each corner of the defensive wall had a doorway – i.e. the initial plan was to have a tower at each of the four corners. However, two bastions were spared in the construction of the fortification, which was in exchange surrounded by a bawn. On the eastern wall one can find a bricked up entrance, the frame of which uses a lintel originally designed for a different location. This bears a ruined inscription engraved: ANNO 1622 IOANN PA: ET LVCAS B.
The walls of the fortification were also provided with an alure (chemin de ronde) running around the inside. These provided access to the flattened rectangular embrasures, which can be closed by a wooden slit. Similar embrasures were used on the towers as well. On the four sides of the fortification walls there were built two machicolations on each side, which protected the area close to the ramparts, while the inverted keyhole-shaped embrasures on the façade were used to control the area outside the ramparts. 
These loopholes were mainly used for small firearms and arquebuses. The ramparts were crowned with a crenellated parapet. In addition to the towers, the chambers built inside the castle walls were already used for storage in 1657. Local people were entitled to a ‘share’ of the fort in proportion to their contribution to its construction, and it was up to the individual/family to maintain it.
The complex had a paramount role in saving lives and preserving goods around 1710, during Rákóczi’s War of Independence , when it provided shelter from the raiders. Storing goods in the castle was still common practice in the first decades of the 20th century, but the complex was increasingly falling into disrepair. The events following the First World War did not favor restoration efforts. 
Earthquakes in 1940 and 1977 further weakened the structure of the former fortification. On 5 September 1944, during the fighting between German and Romanian troops in the area of Aita Mare, the northern section of the wall was hit by cannon shells.
The most important repairs were carried out in the 1990s: the gate tower was renovated in 1993, the north-western tower was restored between 2000 and 2002, and finally the entire building was restored between 2019 and 2021.