 As a result of this retreat, Matilda was never formally declared Queen of England, and was instead titled "Lady of the English" ().Robert was captured following the Rout of Winchester in 1141, and Matilda agreed to exchange him for Stephen.Matilda became trapped in Oxford Castle by Stephen's forces that winter, and to avoid capture was forced to escape at night across the frozen River Isis to Abingdon, reputedly wearing white as camouflage in the snow.