Henry VI was the youngest monarch ever to succeed to the English throne, becoming king upon the death of his father Henry V at the age of only nine months. Because his mother was Catherine of Valois, and in accordance with the Treaty of Troyes, he also became King of France only two months later. He was never able to assert this right effectively, but unlike his father, however, he opted for a policy of relative peace with France. After he came of age in 1437, he soon had a marriage arranged with Margaret of Anjou, niece of the French Queen. She was to go on to hold an important position in English politics, effectively ruling the kingdom in lieu of her husband during his bouts of insanity in 1453-4.