The ocean in medieval times was a thing of great mystery to the ordinary medieval peasant. However to the explorers, the church and the educated the sea was a dangerous place. The ocean began to fascinate people in the time of the early Greeks. The Titans ruled the earth in the beginning, and Oceanus, son of Uranus and Gaea was one of them.
"In him [Oceanus] Homer salutes the essence of all things, even the Gods, and regards him as a divinity whose power was inferior to none but Zeus'"
He was the father of all the rivers and lakes of the world. But then the Olympians rebelled against the Titans, Zeus drove Cronus into the western ocean. When Zeus had taken his place as head of the gods, not even the oceans tides could defy him.
According to the Odyssey there were remote paradise islands in the ocean where time does not apply. Not every Island was paradise though. At Aeaea Odysseus learns of the whereabouts of the entrance to the land of the dead, to which he must travel. When his ship reaches the farthest areas of the ocean he finds it wrapped in fog, a dark place where the unhappy Cimmerians live. These among many other beliefs were carried forward to the medieval times, through oral tradition and through the writings of people like Homer.
Another major factor influencing the medieval view of the ocean is the ideology of the Desert Fathers. The desert fathers were holy men that lived in the near east, who became disillusioned with the materialistic culture of the time and wandered out into the desert as hermits. They were seen as heroes in their time and were revered as wise men. They were sought out by people wanting guidance and gradually became famous for their way of life. They went out to the desert for solitude, to be `warriors of God' and test themselves against the rigours of life and to purge themselves of their internal demons. In the North there were no deserts, so the monks had to go for the only other thing that would give them the isolation they desired. The Sea.
"Adamnán refers to a certain Báitán who asked for St. Columba's blessing before setting out in search of a desert place in the sea (in mari herimum) ... It is clear from Adamnán that eremitical sea-voyages such as these were a familiar enough feature of the religious environment of the C7th"
The Monks formed monasteries on remote islands off the Irish coast, for example Skellig Michael, Co. Kerry and Inishmurray, Co. Sligo. They viewed themselves as white martyrs, leaving their families and friends to do good work for God and the church. Living in discomfort in little beehive huts sleeping on stone beds on windswept rocky crags in the ocean, they scraped together a living selling their crafts through an independent agent.
The idea of penance and exile is closely tied up to the idea of white martyrdom, often there were civilians on the monastery and they were there to repent for their sins. They spent a certain length of...