You've probably heard of Anne Neville, and Warwick the Kingmaker (Richard Neville) but do you remember Anne Neville's elder sister, Isabel? Isabel was almost queen herself (well kinda) as well the Duchess of Clarence (and mother to the futrue Margaret Pole.) So Isabel is a pretty important character in her own right, why have we forgotten about her?
Isabel was born in 1453 (ish) and I'm sure was a slight disappointment. (I'm sure Warwick and Anne Beauchump were hoping for a Kingmaker Jr. :) ) For the first couple years of her life, she was an only child, and given Warwick's wealth, I'm sure had the best nurses and tutors. Then, about 4 years later, her sister Anne was born. (again, Warwick and Mrs. Warwick were hoping for a boy.)
Anne and Isabel then grew up together in their parent's household. It was there that Anne met her future husband, Richard III. Isabel, however, had never met Clarence. Her marriage became a great deal to her parents once Warwick was in power and Edward IV was king. But, by the time Isabel was old enough her father wanted to dethrone Edward and put Clarence on instead. Isabel was then married to George, Duke of Clarence to seal the alliance.
As far as personality goes, i believe Isabel was the indoorsy type, and very kind to everyone she met. She cared not for politics like her father did and just wanted to raise her children. She adored her family and stayed true to the Yorkist cause. Isabel's story is one of "What if..." because if things had gone according to plan, there could've been King Edward VI, son of the Duke of Clarence!