The image of Britannia () is the national personification of Britain as a helmeted female warrior holding a trident and shield. An image first used by the Romans in classical antiquity, the Latin Britannia was the name variously applied to the British Isles, Great Britain, and the Roman province of Britain during the Roman Empire. The Roman Britannia was typically depicted reclining or seated, with not a trident but a spear and shield, appearing on Roman coins of the 2nd century AD. The classical allegory was revived in the early modern period. On coins of the pound sterling issued by Charles II of England, Scotland, and Ireland, Britannia appears with her shield bearing the Union Flag. To symbolise the Royal Navy's victories, Britannia's spear became the trident in 1797, and a helmet was added to the coinage in 1825.
By the 1st century BC, Britannia had replaced Albion as the prevalent Latin name for the island of Great Britain. After the Roman conquest in 43 AD, Britannia came to refer to the Roman province that encompassed the southern two-thirds of the island (see Roman Britain). The remaining third of the island, known to the Romans as Caledonia, lay north of the River Forth in modern Scotland. It was intermittently but not permanently occupied by the Roman army. The name is a Latinisation of the native Brittonic word for Great Britain, Pretanī, which also produced the Greek form Prettanike or Brettaniai.
