On this day of 6 April in 1231, William Marshal II, the 40-year-old earl of Pembroke, died suddenly, less than a week after attending the marriage of his sister Isabel to Richard of Cornwall, brother of King Henry III and Marshal’s now 16-year-old widow Eleanor. The king was so distraught that he vowed to be buried at the New Temple together with William II and his father William I, who had knighted Henry before his first coronation. No one could know it at the time, but Marshal’s death set off a chain of events that would plague Henry for the rest of his reign. As William and Eleanor had no children, Marshal’s brother Richard succeeded him as the earl of Pembroke and caused Eleanor all kinds of difficulties over her dower, the one-third portion of William’s estate that was due her. He then raised rebellion against Henry, which cost him his life. To help end the conflict, Eleanor took a vow never to remarry, that way her dower lands would revert back to the Marshal family. But she broke her vow to marry a foreign adventurer named Simon de Montfort and together these two grumbled and complained about how she had been cheated by Richard Marshal. When Simon de Montfort raised rebellion against Henry in 1263, Eleanor’s dower was one of the grievances behind his disaffection. Not until 1286, long after the principals were all dead, was the issue finally settled, 55 years after William’s untimely, and much regretted, death.