Pennsylvania - The Largest Gambling Debt in History?

On this date in history (March 4, 1681) Charles II of England granted a land charter to William Penn for the area that would later become Pennsylvania. The historical question that needs answering is why Charles II would do this in the first place - seeing how the Quakers and William Penn weren't exactly darlings of the English Court. The book Roll the Bones: The History of Gambling may hold the key:

The answer may lie in the relationship between Charles (II) and Sir William Penn, the young Quaker's father. Although he had first sided with Parliament in the Civil War, Sir William became a favorite of Charles after the Restoration, commanding the English navy during a war with the Dutch. On his deathbed, sir William secured a royal promise to care for his sons. It was also rumored that the inveterate gambler Charles never paid the elder Penn for a gambling debt of 16,000 pounds and that this granting of of Pennsylvania to William Penn satisfied this debt. If true, the birthplace of American liberty was the largest marker (gambling debt) payment ever.

I find the gambling connection to the two most famous American Quakers amusing. William Penn probably got the land grant of Pennsylvania to settle a gambling debt and Richard Nixon paid for his first Congressional campaign with funds he won playing poker in the Navy.