The Romans invaded Britain in 43 AD during the reign of Emperor Claudius, subsequently conquering much of Britain, and the area was incorporated into the Roman Empire as Britannia province. The best-known of the native tribes who attempted to resist were the Catuvellauni led by Caratacus. Later, an uprising led by Boudica, Queen of the Iceni, ended with Boudica's suicide following her defeat at the Battle of Watling Street. The author of one study of Roman Britain suggested that from 43 AD to 84 AD, the Roman invaders killed somewhere between 100,000 and 250,000 people from a population of perhaps 2,000,000. This era saw a Greco-Roman culture prevail with the introduction of Roman law, Roman architecture, aqueducts, sewers, many agricultural items and silk. In the 3rd century, Emperor Septimius Severus died at Eboracum (now York), where Constantine was subsequently proclaimed emperor.