Фреска

[Nathan Ross]

what century the Romans started using tunic with sleeves?

The long-sleeved tunic seems to have come into common use during the first half of the third century, although it was probably worn before that in certain areas. Severan tombstones still show the old short-sleeved or sleeveless tunic, but wall paintings from Dura Europos (before AD240) show the sleeved tunic, and roughly contemporary tombstones from II Parthica at Apamea show the same. So some time between AD200 and 230 would be the best approximate date, I would guess.