in communion with the Church of England in 1804. Other denominations included Baptists, Congregationalists and Methodists. In the twentieth century, existing Christian denominations were joined by the Brethren and Pentecostal churches. Although some denominations thrived, after World War II there was a steady overall decline in church attendance and resulting church closures for most denominations. Other denominations in Scotland include the Jehovah's Witnesses and the Church of Jesus Christ of Latter-day Saints. Middle Ages Early Christianity Christianity was probably introduced to what is now southern Scotland during the Roman occupation of Britain. While the Picts and Scots away from Roman influence would have remained pagan, most scholars presume that Christianity would have survived after the departure of the Romans among the Brythonic enclaves such as Strathclyde, but retreated as the pagan Anglo-Saxons advanced into what is now the Lowlands of Scotland. In the sixth century, missionaries from Ireland were operating on the British mainland. This movement is traditionally associated with the figures of St Ninian, St Kentigern and St Columba. Ninian is now regarded as largely a construct of the Northumbrian church, after the Bernician takeover of Whithorn and conquest of southern Galloway. The name itself is a scribal corruption of Uinniau ('n's and 'u's look almost identical in early insular calligraphy), a saint of probable British extraction who is also known by the Gaelic equivalent of his name, Finnian. Little is known of St Kentigern (died 614), who probably worked in the Strathclyde region. St Columba was probably a disciple of Uinniau. He left Ireland and founded the monastery at Iona off the West Coast of Scotland in 563 and from there carried out missions to the Scots of Dál Riata, who are traditionally seen as having colonised the West of modern Scotland from what is now Ireland, and the Picts, thought to be the descendants of the Caledonians that existed beyond the control of the Roman Empire in the North and East. However, it seems likely that both the Scots and Picts had already begun to convert to Christianity before this. Celtic Church Early Pictish religion is presumed to have resembled Celtic polytheism in general. The date at which Pictish kings converted to Christianity is uncertain, but there are traditions which place Saint Palladius in Pictland after leaving Ireland, and link Abernethy with Saints Brigid and Darlugdach of Kildare. Saint Patrick refers to "apostate Picts", while the poem