In Love Without End, his complex and thoughtful re-telling of one of the most fabled love stories of all time, Melvyn Bragg has Peter Abelard write to Heloise the brutal words: “My love should be called lust.”

Heloise has been raised in a nunnery and she is known for her learning and her knowledge of classical authors. In 1117, when she is probably in her early twenties, she is brought to live in Paris by her supposed uncle, the cleric Fulbert. Fulbert is, in fact, her proud and possessive father.

Abelard is the greatest teacher of the age, cutting through the unexamined dogmas of the church with his rational arguments. The celibate Abelard is drawn to Heloise by her reputation much as she is drawn to him. He is engaged as her tutor and attraction becomes an overwhelming love that goes beyond reason. Abelard, the great logician, says that their love “eludes explanation... It exists because I know it exists but I do not know how it exists.”

He is concerned to explore the nature of the developing love of Abelard and Heloise as they would have understood it in their day caught up in the beliefs of the time and to examine it against the understanding we might have today of such passions.

To that end the novel has a second plot centred on a university teacher, Arthur, and his daughter, Julia, who are staying in Paris. Arthur is writing a novel on Abelard and Heloise. The father shares his work as it progresses with his challenging daughter but in the process gradually reveals affinities in his own life and love with that of his medieval counterparts.

The love of Abelard and Heloise is discovered. The pregnant Heloise is smuggled away and Abelard returns to Paris. There he is castrated by an angry Fulbert and jealous rivals – the scene itself is economically and skilfully crafted. He enters a monastery and Heloise, against her will, submits to the harsh disciplines of a nunnery.

In these circumstances their love undergoes its transformation. Abelard’s denial of his love as lust sinks inside Heloise “like a block of ice that seemed, infinitely slowly, to transfer the chill to her heart.”

Slowly she realises that his intention was not to wound her, but to free her from herself. She recalls his prayer for “those whom Thou hast parted for a time on earth, unite for ever to Thyself in Heaven.”

It was through his wound, through his castration, that God had shown them the danger they were in and led them back to Himself.

“He had favoured them, rescued them, graced them.”

She understands that though they are apart, theirs is a “love without end”.

This is a well-crafted story which, like all the best fiction, makes us ask questions about the way we understand ourselves.