Persistent object oriented architectures have been researched for many years, deriving initially from the Manchester University Atlas machine. In reality, however, few actual implementations of persistent architectures exist. In the first half of this paper an examination of four well known designs is carried out, namely the System/38, Monads, Mutabor and the Rekursiv. Each machine's object management model is explained, along with an analysis of the design decisions made. Following this, a discussion concerning the ideal persistent architecture is presented, suggesting design decisions which should be considered in any future persistent architecture.