Isabella was Fletcher Christian's first cousin. The Curwen lineage is an ancient and noble one which can be traced back to pre-Norman times. Curwens represented their county in Parliament for 18 terms from 1371 onwards. They held the posts of Knights of the Shire and High Sheriffs who played a major part in the bloody border wars.
Isabella Curwen was born on October 2nd 1765, the only child of Henry Curwen of Workington Hall who died when she was thirteen, leaving her the heiress of the estate and huge mining interests. John Christian, her cousin, was made her guardian and later became her husband. It was John who bought for her the island on Windermere which was named Belle Isle in her honor.