How about Catherine de' Medici?
http://en.wikipedia.org/wiki/Catherine_de'_Medici#Queen_of_France
Crying Uncle yet, James?
http://en.wikipedia.org/wiki/Catherine_de'_Medici#Queen_of_France
Throughout Henry II's reign, he excluded Catherine from influence and instead showered favours on his mistress, Diane de Poitiers. Henry's death in 1559 thrust Catherine into the political arena as mother of the frail fifteen-year-old King Francis II. When he too died in 1560, she was appointed regent on behalf of her ten-year-old son King Charles IX and was granted 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.
Crying Uncle yet, James?