Ossian's poems were made famous by James Macpherson who found his Gaelic epic in the 18th century. However, there are doubts as to whether these poems were actually written by Ossian, or whether Europe has become acquainted with the Celts through Macpherson. The verses that Macpherson sent out into the world were wildly popular in his time, appreciated by Goethe and Herder, and had a major influence on German Romanticism. The poems were even compared and praised with the work of Homer. Even Napoleon Bonaparte knew the work and commissioned the painter Ingres to paint the 'Dream of Ossian'.
The book by Lady Augusta Gregory , the woman who first wrote the great Irish sagas in a popular retelling, describes the wonderful story of Ossian's mother.
The story of the fair deer
During a hunt, Ossian's father, Fionn of Finn of the Fianna family of Erin (Ireland), meets a fair roe deer that turns into a beautiful woman in the evening. She had rejected a lover, the Dark Druid, who in the past had turned her into a roe deerfor revenge. A servant took pity on her and told her to try to join the circle around the Fianna, so that the Dark Druid would lose his power over her.
In this regard, it is necessary to mention why the Dark Druid lost his power when the roe joined the Fianna clan.
If one wanted to be included in this clan, one had to be initiated. Fianna means 'landless', people without a homeland. The expression 'landless' has been a universal concept throughout all times and indicates that we are dealing here with a 'pupil of a mystery school'.
One who was ‘landless’ broke with their family, with their own clan into which they were born and voluntarily joined the clan of the Fianna.
The binding between the members of the Fianna clan was of a spiritual origin. The Fianna apparently possessed power greater than that of the Dark Druid, hence the roe was referred to that circle.
Then when the deer meets the Fianna, she becomes the beautiful woman she once was. Finn gives her his love, even foreswears the hunt, and takes her as his wife.
One day when her husband is absent, his wife disappears again. Finn searches for her for seven years without ever seeing his beloved wife again. At a certain point, he meets a naked youth, found by his dogs. The boy, who is very beautiful, cannot speak, and Finn recognizes his wife's features in him. He takes the boy with him and when he can speak, he tells a curious story. The boy had been raised by a roe deer and he loved her very much. Sometimes a man would come and talk to the deer, but the deer always kept aloof from him. Then the man became furious and one day he beat her with a hazel rod so that she was forced to follow him. The boy wanted to follow her, but couldn't move. The deer watched him with tears of sorrow. He was left in the forest wailing with anger and frustration and lost his senses until Finn's dogs found him and he awoke.
Finn calls the lad Ossian. The name Ossian or Oisin means ‘little deer’ and is appropriate for the son whose mother is enchanted into a deer. Ossian writes beautiful poems for the clan and later he was one of the good warriors in the lineage of the Fianna.
The following poem is from Ossian works by James Macpherson:
O thou that rollest above,
round as the shield of my fathers!
Whence are thy beams, O sun!
thy everlasting light!
thou comest forth in thy awful beauty;
the stars hid themselves in the sky ;
the moon, cold and pale,
sinks in the western wave;
but thou thyself movest alone.
Who can be a companion of thy course? 
The Ossian Poems were published by the Ossian Society in the middle of the 19th century, and from then on they became wildly popular. The Europeans experienced a world of fairies, heroes, gods and demons that had long been forgotten. It was suspected that these stories had been of great significance. People also began to compare these stories with other mythologies, but that was difficult and almost impossible.
In any case, it became clear that the mythologies had arisen before the Christian era and that we must see the main characters in these stories as direct descendants or Avatars. They are the reincarnations of gods in a human body. The idea of rebirth was a painful subject for the Christian writers and hence quite a bit of confusion has arisen. They changed the stories and sometimes adapted them with the ideas of heaven and hell.
For example, Cuchulainn is said to have been an Avatar of the deity Lug. The Irish had no qualms at all with some figures appearing now as human beings and then again as a deity. To a people who were clairvoyant to a high degree, these stories were nothing out of the ordinary.
 James Mac Person, The Works of Ossian, 1765
 Lady Augusta Gregory, Gods and fighting men, 1905
 Hans Gsänger, Irland. Insel des Abel. Die irischen Hochkreuze [Ireland. Isle of Abel. The Irish high crosses], Verlag Die Kommenden, 1969
 Jakob Streit, Sonne und Kreuz [Sun and Cross], Freies Geistesleben, Stuttgart 1977