Year 9 of Trajan's reign in Egypt — 105/106 AD — falls squarely within the period of his Dacian campaigns, and the Alexandria mint was operating under the administrative structures of Roman Egypt rather than the imperial mint system. Alexandrian billon tetradrachms circulated exclusively within Egypt's closed currency zone; Roman silver was not legal tender there, and Egyptian coins could not legally leave the province. Milne 541 is well-documented, with Dattari's numbering drawn from his exceptional Cairo collection assembled in the early twentieth century.
Year 9 of Trajan's reign in Egypt — 105/106 AD — falls squarely within the period of his Dacian campaigns, and the Alexandria mint was operating under the administrative structures of Roman Egypt rather than the imperial mint system. Alexandrian billon tetradrachms circulated exclusively within Egypt's closed currency zone; Roman silver was not legal tender there, and Egyptian coins could not legally leave the province. Milne 541 is well-documented, with Dattari's numbering drawn from his exceptional Cairo collection assembled in the early twentieth century.