Almost no Mithraic scripture or first-hand account of its highly secret rituals survives; with the exception of the aforementioned oath and catechism, and the document known as the Mithras Liturgy, from 4th century Egypt, whose status as a Mithraist text has been questioned by scholars including Franz Cumont. The walls of mithraea were commonly whitewashed, and where this survives it tends to carry extensive repositories of graffiti; and these, together with inscriptions on Mithraic monuments, form the main source for Mithraic texts.