The Roman settlement was founded around AD 50. It grew to a significant town, despite the attentions of Boudicca in AD 61. It had municipium status and grew steadily - by the early 200s it covered an area of about 125 acres, behind a deep ditch and wall. It had a forum, basilica and a theatre, most of which were destroyed during a fire around AD 250?. The town was rebuilt in stone rather than timber at least twice over the next 150 years. Occupation by the Romans ended around 500.
The post-Roman development of St Albans came about from the death of [St Alban]? in 209? - the first English Christian martyr. There was a shrine on the site of his death and in the 400s a monastic church was constructed, followed by an Anglo-Saxon monastery. The cathedral was started in 1077? by [Paul de Caen]?, the 14th Abbot, it was completed in 1089? and was 350 feet long with a tower and seven apses.