Tacitus writes that an exiled Irish prince was with Agricola in Roman Britain and would return to seize power in Ireland. Juvenal tells us that Roman "arms had been taken beyond the shores of Ireland". In recent years, some experts have hypothesized that Roman-sponsored Gaelic forces (or perhaps even Roman regulars) mounted some kind of invasion around 100 AD,[15] but the exact relationship between Rome and the dynasties and peoples of Hibernia remains unclear.