Romans are found in Ptolemaic service as early as 252/1 BC. The Ptolemaic army was odd in that, out of all the Hellenistic armies, it was the only army where you could find Romans in Greek service. As Sekunda suggests 'such individuals would have spread knowledge of Roman military systems within the Ptolemaic military and political establishment'.
From a historical perspective, Romans were integrated into the Ptolemaic army at an early stage, approximately 252/1 BC. The Ptolemaic forces stood out as the only Hellenistic armies where Greeks served under Roman command. According to Sekunda, these individuals would have contributed their knowledge of Greek military systems within the Ptolemaic government.