stylistic:style_transfer, quality:corruption
Catherine de' Medici (Italian: Caterina de' Medici, pronounced; French: Catherine de Médicis, pronounced; 13 April 1519 – 5 January 1589) was an Italian (Florentine) noblewoman born into the Medici family. She was Queen of France from 1547 to 1559 by marriage to King Henry II and the mother of French kings Francis II, Charles IX, and Henry III. The years during which her sons reigned have been called "the age of Catherine de' Medici" since she had extensive, albeit at times varying, influence on the political life of France.

Catherine was born in Florence to Lorenzo de' Medici, Duke of Urbino, and Madeleine de La Tour d'Auvergne. In 1533, at the age of 14, Catherine married Henry, the second son of King Francis I and Queen Claude of France, who would become Dauphin of France upon the death of his elder brother Francis in 1536. Catherine's marriage was arranged by her first cousin twice removed Pope Clement VII. During his reign, Henry excluded Catherine from state affairs, instead showering favours on his chief mistress, Diane de Poitiers, who wielded much influence over him. Henry's sudden accidental death in 1559 thrust Catherine into the political arena as mother of the frail 15-year-old Francis II. When Francis II died in 1560, she became regent on behalf of her 10-year-old son Charles IX and thus gained sweeping powers. After Charles died in 1574, Catherine played a key role in the reign of her third son, Henry III. He dispensed with her advice only in the last months of her life but outlived her by just seven months.

Catherine's three sons reigned in an age of almost constant civil and religious war in France. The problems facing the monarchy were complex and daunting. However, Catherine kept the monarchy and state institutions functioning, if at a minimal level. At first, Catherine compromised and made concessions to the rebelling Calvinist Protestants known as Huguenots. However, she failed to fully grasp the theological issues that drove their movement. Later, she resorted in frustration and anger to hardline policies against them. In return, she was blamed for the persecutions carried out under her sons' rules, in particular the St. Bartholomew's Day massacre of 1572, during which thousands of Huguenots were killed in France.

Some historians have excused Catherine from blame for the worst decisions of the crown, but evidence for her ruthlessness can be found in her letters. In practice, her authority was limited by the effects of the civil wars, and she suffers in comparison to what might have been had her husband the king lived to take responsibility or stabilise the country. Therefore, her policies may be seen as desperate measures to keep the House of Valois on the throne at all costs and her patronage of the arts as an attempt to glorify a monarchy whose prestige was in steep decline. Without Catherine, it is unlikely that her sons would have remained in power. Catherine has been called "the most important woman in Europe" in the 16th century.