Isabella of Gloucester (c.1160/1166 - 1217) was the youngest (surviving) daughter of the 2nd Earl of Gloucester, William FitzRobert, and Hawise of Beaumont, daughter of the Earl of Leicester. We call her Countess of Gloucester now, but she was actually Queen of England. To explain, we have to step back and talk about King Henry II and his youngest son,
John.
Henry seemed to consider John his favorite, perhaps because John was the only one of Henry's son who never rebelled against his father and tried to take the throne. I think Henry understood that John was not likely to inherit the throne: he had brothers who were ahead in line of succession, and were also aggressive enough that they would easily usurp the throne from John.
Henry dealt with this situation by increasing John's real estate holdings, and therefore the revenues from said properties. He did this sometimes at the expense of Henry's nobles, appropriating their estates and giving them to John. In September 1176, Henry argued with Isabella's father, William. To resolve the dispute and ensure amity between earl and king, William promised Isabella's hand to John in marriage, and to recognize John as the heir to the estates of Gloucester. (Even if William and Hawise had another son, John would still get half the estates.)
Well, William died in 1183, and even though Isabella had sisters, Henry declared Isabella sole heir to all of her father's lands, and also declared her his ward, giving him control over all the Gloucester property. He retained this control until he died in 1189, at which point Richard became king and Isabella was given to John in marriage. (This was risky in the eyes of the Church and its rules of consanguinity, since Isabella and John were closely related, having the same great-grandfather.) Since they did not get a dispensation from the pope to override the consanguinity issue, the Archbishop of Canterbury, Baldwin of Forde, put John under Interdict. The Interdict was removed by the papal legate, but the marriage was never condoned.
It stayed intact, however, and when Richard I died in 1199, John became king in May. John then requested that his marriage to Isabella be annulled on the grounds of consanguinity; this was granted in August.
But John kept the lands.
Isabella had a nephew, Amaury, Count of Évreux. John gave him the title Earl of Gloucester. He died in 1213, and Isabella became Countess of Gloucester. It is possible that she was never formally crowned, but she was married to the King of England, for however brief a time, making her something of a "forgotten queen." In fact, her likeness is hard to find. The illustration above is a generic royal woman.
Isabella was not left out in the cold. She had two advantageous marriages after John, and I'll tell you about those tomorrow.