Dicuil was a Geographer and Monk who is believed to have lived in an Irish Monastery in the Frankish Kingdom. He taught at a school of Louis the Pious and wrote astronomical and geographical works, quoting the works of many classical Latin writers.
His works Luber De Mensura Orbis Terrae (Concerning of the Measurement of the World), written in 825 and translated to English by James J. Tierney in 1967, is a correction of the measurements of the known provinces of the Earth that were carried out under the orders of Emperor Theodosius. It is worth noting that Dicuil states that he does not believe that all of his own corrections are correct and in time expects them to, to be re-written. In this work he states “There is another set of small islands, nearly all separated by narrow stretches of water, in which for nearly a hundred years hermits sailing from our country, Ireland, have lived. But just as they were always deserted from the beginning of the world, so now because of the Northman pirates they are emptied of anchorites, and filled with countless sheep and very many diverse kinds of sea-birds. I have never found these islands mentioned in the authorities”. Northman pirates referring to, of course, vikings and anchorites – devout religious people seeking solitude.

Íslendingabók is a short summary of the history of Iceland, it was written by Ari Þorgilsson between 1122 – 1133, around 300 years after the Irish monks had supposedly inhabited the island, as a summary of Icelandic history, from the first Norwegian inhabitants up to the time in which it was written.
Ari Þorgilsson himself was known as Air the Wise and was the most prolific Icelandic medieval chronicler. He studied at a school in Haukadalur under Teitur Ísleifsson, son of Ísleifur Gissurarson (the first Bishop in Iceland). Through his classical education, Ari learnt to tell in the tone of Latin chronicles, however he is renowned for telling in the traditional Icelandic oral telling of stories.
In the English translation of Íslendingabók, it states that Iceland was first settled in the days of Haraldr inn hárfagri. Ari Þorgilsson, states that he was told this tale by his foster father, his uncle and the daughter of Snorri the chieftain. The Norwegian who first travelled to Iceland, Ingólfr, stated that “at that time, Iceland had woods growing between the mountains and the shore. Christians were here then whom Norðmenn call Papar”. The Papar are said to have left as they did not want to live alongside heathens. However, they left books, bells and croziers, which could be used to tell that they were Irishmen.
In more modern times, Dr Kristján Ahronson a Celtic archaeologist, concluded that Kverkarhellir, a man made cave that was discovered in South Iceland, was created around 800 CE. Before the Norwegian settlement of Iceland in 874 AD.
Ahronson found that the waste material displaced from the Kverkarhellir cave can be dated to around 800, suggesting that initial settlers inhabited Iceland, before the first Norwegian settlers arrived.
In his projects he states “in Iceland’s caves, we discovered sculpture with persuasive connections to Scotland’s early medieval monastic sites”. The Kverkarhellir cave and other similar sites were marked by crosses that bare resemblance to that of sculptures in Britain and Ireland.