Catherine de Medici by Leonie Frieda

Like her contemporary Elizabeth I of England, Catherine de Medici was inspired by a single-minded devotion to the interests of her country, France, which in her long widowhood she effectively ruled. But the differences were vast.

Elizabeth inherited the throne from her father, while Catherine came from a family of Florentine bankers, grand but non-royal.

When she married the future Henry II, younger son of Francis I, she was mercilessly snubbed by the French grandees, most of whom had not an iota of her intelligence, courage, loyalty and patience. Catherine eventually had 10 children; Elizabeth none. But Catherine had to endure her husband's besotted devotion to his mistress, Diane de Poitiers.

Catherine's childhood was appalling. Both her parents died before she was a month old; she was neglected and in acute danger. (Her husband's was worse: aged five, he and his brother were handed over as hostages to Spain, where they spent four years as prisoners, denied care of any kind.) For a decade after Catherine's marriage in 1534, she had no children, but made up for it in the next 10 years. The sons were sickly and short-lived, but they attached her husband more firmly to her. He began to appreciate her great qualities, before being killed in 1559, tilting in a tournament.

At 40, she was described as "not beautiful, but a very distinguished looking woman... with a pleasant smile or a few well chosen words for all her guests" and "a very good and fearless horsewoman, who rode far and fast". Her eldest son, the first husband of Mary Queen of Scots, died a year later aged 16. The second surviving son, Charles IX, was to die aged 24. The third, Henry III, survived until the year of his mother's own death.

In these years, when the national unity of France was slowly emerging, royal life was a game of international chess. The players often found themselves pawns in someone else's game, with kings, queens and popes always apt to be taken by unexpected death - whereupon the whole dangerous kaleidoscope was transformed again.

Catherine's own aims remained simple: peace and prosperity for France, strengthened by glorious alliance-building marriages for her children, and a return to the powerful monarchy of her husband and his father.

Many eggs came to be broken in the making of this omelette. After her earlier policy of tolerance, her ruthlessness inevitably increased.

But by the most significant match of all, between her youngest daughter Margot and Henry of Navarre, the French monarchy gained - after many vicissitudes - another two centuries of existence.

Catherine's life was so complicated, covering some of the most savage civil wars in European history, that even an experienced biographer might quail before it. But Leonie Frieda is so successful at making the long story intelligible that it is hard to remember this is her first book.

Not only has her industry been formidable; she avoids getting bogged down in detail, and keeps the story moving. The reader seldom loses sight of the Queen's talents in dealing with innumerable, often insoluble problems. This is a masterly biography, and a fascinating one.