The name Derry comes from the Irish Doire which means oak grove, this name was given to the small settlement on the hill that later became the walled city of Londonderry because it contained a large number of oak trees. The hill was once an island with the River Foyle on one side and wetlands on the other side, since then the River Foyle has moved significantly east and the wetlands are dried up and are now the Bogside/Brandywell.
It is believed that there were forts owned by local kings on the island watching the Foyle and in the 6th century is was given away by the kings to become a religious settlement. Exact details of the early religious settlement are unclear as there is little evidence left of the monastery but the founding is credited to St Columba(Cholmcille).
St Columba was an Irish abbot and missionary evangelist from what is now Donegal that spread Christianity to parts of Scotland and Ireland in the 6th century. According to information from the 12th century St Columba directly founded his first monastery here, other evidence suggests that the monastery was founded by Fiachra mac Ciaráin who was a cousin of St Columba.
Either way the connection with St Columba is engrained in the history of the city and many things have been named as St Columba including St Columb’s Park and St Columb’s Cathedral. Between the 6th Century and 11th century Doire Calgach as it was known at the time is believed to have been primarily a monastic settlement.
In the 12th century the settlement was known as Doire Cholmcille, it was part of the family of monasteries associated with St Columba and then became known as head of Columban monasteries in Ireland. There was a large church known as Teampall Mór meaning Great Church, that was on the site of the Long Tower Church & St Columb’s Heritage Centre that was believed to be the site of the original monastery although it’s now thought to have been on the site of St Augustine’s Church. Many stories were written in the abbey of Derry during the 12th century about the life of St Columba that have been part of city’s story since medieval times till the present day.
Over the next few hundred years there was some settlement in the area by Norman colonists, in the 14th century it was acquired by the 2nd Earl of Ulster Richard de Burgh and became part of the Earldom of Ulster until it’s collapse. It remained a small settlement and managed to avoid any major damage from Viking raids in the 14th Century who sailed up the loughs and rivers in the area.