Anne Somerset, Countess of Northumberland

Anne Percy, Countess of Northumberland (née Somerset; 1538 – 17 October 1596) was an English noblewoman and one of the instigators of the Northern Rebellion against Queen Elizabeth I of England. To avoid punishment for her prominent role in the failed insurrection, Anne, along with her infant daughter, was forced into exile in Flanders, where she spent the rest of her life involving herself in Catholic plots and maintaining contact with the other English Catholic exiles. In Liège while living on a pension from King Philip II of Spain, she wrote Discours des troubles du Comte du Northumberland. Her husband Thomas Percy, 7th Earl of Northumberland, who had led the rebellion, was executed for treason. Three of her daughters were left behind in England and raised by their paternal uncle, Henry Percy, 8th Earl of Northumberland.

Lady Anne was born in 1538, the daughter of Henry Somerset, 2nd Earl of Worcester and Elizabeth Browne, daughter of Sir Anthony Browne and Lucy Neville. She had four brothers and three sisters. She had also a half-sister, Lucy by her father's first marriage to Margaret Courtenay. Anne's mother had been a lady-in-waiting to the queen consort Anne Boleyn and one of the main informants against her; she was also rumoured to have been a mistress of King Henry VIII.

Anne was a devout Roman Catholic.

On 22 June 1558, she married Thomas Percy, 7th Earl of Northumberland, one of the most powerful nobles in Northern England, and like Anne, he practised the Catholic religion. He was the nephew of Henry Percy, 6th Earl of Northumberland, the former suitor of Anne Boleyn.