The Christianisation of Scotland was the process by which Christianity spread in what is now Scotland, which took place principally between the fifth and tenth centuries. Christianity was probably introduced to what is now Lowland Scotland by Roman soldiers stationed in the north of the province of Britannia. After the collapse of Roman authority in 410 CE/AD, Christianity is presumed to have survived among the British enclaves in the south of what is now Scotland, but retreated as the pagan Anglo-Saxons advanced.