The excavations of the Mithraeum by the Dutch in the mid 20th century proved to have found leftover fragments of frescoes. The Mithraeum had been embellished with paintings, and these frescoes, in particular, contain imagery and iconography which depict particular beliefs in the Mithraic cult as well as elements of initiation. One of the frescoes on the left wall within the Mithraeum of the Roman Church includes a depiction of a cult processional towards figures Mithra and Sol, with those participating in the cult holding various objects as they make their way to their deities. Both the left and right walls in the Mithraeum of Santa Prisca have remnants of paintings which depict different scenes and include several figures; however, due to destruction, some of the images are difficult to make out. The left wall of the temple shows several walking male figures, some youthful and full of energy. They are seen in brown and yellow color tunic holding objects like pans, terracotta and glass vessels, even animals like chickens. Another figure in the painting is seen standing, wearing a red tunic and is depicted with a raven face mask and proffering an oblong dish. Other depictions within the frescoes of the Mithraeum include soldiers holding their military bags. Within the Mithraic cult, there is an initiation of seven grades, which are also referred to as the seven planetary grades of salvation. It is thought that this fresco in Santa Prisca is a depiction of the seven grades of initiation, though it is hard to be certain with only the fragmentary evidence that remains. The right wall fresco in the Mithraeum features the seven grades arranged in the exact order (followed by their symbols):