Elizabeth Chadwick, The Champion

Here is a little bit about the book , personally I found it hard work for about the first half of the book

Alexander and Hervi de Montroi, half-brothers with no inheritance, meet in France. Hervi is a professional jouster and Alexander, fleeing the beatings of an English monastery, needs a trade. Despite misgivings, Hervi takes him on as his squire, introducing him to the travellers' immoral lifestyle. He befriends a girl, Monday, taking care of her after her parents die until, pregnant with Alexander's child, she leaves, finding shelter in a castle as a seamstress. Noticed by King John, she becomes his mistress in England, bearing his son and gaining a house. Meanwhile, Stefan has returned to England too, in the pay of an Earl - they meet again at court and, now older, fall in love. They have the King's blessing, but Monday's grandfather, now heirless, sees her as a way to gain power. She escapes his kidnapping to be reunited with Alexander on the land granted to him by the Earl.