Diepoldsberg with the church lies on a ridge formed between the Inn and Prien glaciers. The place was first mentioned in 1175 and the church in 1195. The substructure of the tower dates from the Romanesque period. Today's late Gothic construction was probably started in 1428. The early baroque furnishings come from Wasserburg masters. The high altar is marked 1650.
The murals were created around 1600. The pilgrimage to Saint Leonhard must have started in the middle of the 17th century. Votive tablets from this period bear witness to this, and reports are already being given of the first rides around Leonhardi. In 1785 there were considerations to demolish the church, which was prevented by donations and allocations. The interior is in rare uniformity from the early to high baroque period. In 1861 a storm tore down the church tower.
In 1975 the exterior was renovated. The early to high baroque furnishings date from the middle of the 17th century in rare uniformity. The high altar is dated 1650. The pulpit and side altars are from the same period, as is the communion trellis. The altar carving dates from around 1730.
The interior was originally dominated by valuable wall paintings from around 1600. During the period of Gothic change from 1864, the neo-Gothic windows were installed and these valuable frescoes were destroyed. They had already been whitewashed with up to seven layers and were only uncovered in 1965.