In 1951, Dr Antun Bauer (then director of the Plaster Cast Museum in Zagreb) noticed the walls in the park in front of the school in Ilok. Investigation determined that they belong to a larger building which cannot be dated to the post-Turkish period. The excavation done in 1957 showed that the walls in front of the school belong to the church of St. Peter the Apostle which is mentioned in historical sources and city plans. It was determined that the church is 60 m long and 17.5 m wide. In September 2006, the archaeological excavation of the church of St. Peter in Ilok was conducted within the project of the Ministry of Culture of the Republic of Croatia “Exploration, restoration and revitalization of cultural heritage Ilok – Vukovar – Vučedol”. The square grid made for the site (with squares measuring 5 × 5 m) was integrated into a larger grid that covers the entire Upper Town. An area of 450 m² was excavated, and the church, 22.9 m long (measured from the top of the apse) and 15.95 m wide, was discovered. Excavation of selected sections showed the great accuracy of the previously-conducted geophysical survey. An apse with buttresses and an altar, the north wall of the church, four pillars and a brick church floor were discovered. During the excavation, traces of earthworks from the second half of the 20th century were found, as well as archaeological excavations from the 20th century, excavations of various installations (lighting for the park that is no longer in use, telephone cables). The walls of the church (apse, north wall of the church and buttresses) were built of large, irregular and unworked stones bound with white mortar, and with a very small amount of fragmented brick used in the construction. Inside the apse, the foundation of a square-shaped altar was discovered. It is built of stone, plaster and to a lesser extent of brick fragments. Inside the apse, the preserved Gothic brick floor was found. The floor appears below the layer of the recently deposited soil (at the end of the 20th century the park was filled up several times), and it is placed on a foundation of white mortar or in places of yellow clay. In the places where the floor has not been preserved, a large amount of rubble is located in which several Gothic-style architectural fragments were found, as well as bricks, and prehistoric, medieval and modern potsherds. Of the large number of finds collected during 2006, stone architectural fragments are the most noticeable and of great importance. Among them, fragments of the ribs of the church vault, fragments of windows, etc. were found. In addition, the find of a fragment of a mould for a Gothic stove tile should be noted. The fragment was found in a recently deposited layer, but if it is taken into account that a mould for stove tile was already found in Ilok, then this find is even more important as it indicates that in the medieval town of Ilok that the Gothic stove tile workshop existed. A larger number of finds from the prehistoric, medieval and modern periods were found, as well as slightly fewer finds from the Roman period. After the excavation was completed, the terrain was covered with geotextiles and soil (Željko Tomičić, Kornelija Minichreiter, Kristina Jelinčić 2007, Hrvatski arheološki godišnjak 3/2006, 36–38).