In a Celtic tribe, the king or queen usually held absolute power and permitted no one else to command military forces.

The first Roman general to visit Britain was Julius Caesar.

After two visits to Britain, Caesar decided to conquer the island for Rome; only his death prevented a Roman invasion in 44 B.C.

Augustus and the other early Roman Emperors after Caesar thought that Britain was too far away and too difficult to conquer.

In A.D 43, Emperor Claudius personally led a successful Roman invasion of Britain.

Britain was finally conquered and made a province of the Roman Empire in A.D. 78.

Gnaeus Julius Agricola, the Roman governor of Britannia at the time of our stories, not only increased the size of Roman territory in Britain but encouraged the British population to adopt Roman customs.

Under Agricola, a network of Roman roads in Britain caused a great increase in trade between Britain and the rest of the Roman Empire.

Rome withdrew its armies from Britain in A.D. 85, shortly after the end of Agricola's term as governor.

Gaius Salvius Liberalis, our new main character in the Unit 2 book, was born in Pompeii and came to Britain after the eruption of Mount Vesuvius.

By the time he arrived in Britain, Salvius had already held important political, military, and religious positions in the Roman government.

As legatus iuridicus or assistant governor, Salvius commanded the Roman army in northern Britannia while Governor Agricola was supervising the law courts and administering the southern territories.

Details of Salvius' life are found in a long autobiography (which he wrote) and on his tomb in Britannia.