Agda Persdotter was reportedly the daughter of the wealthy merchant and city Councillor Peder Klemetsson, who resided by the gate of St Nicolai in Stockholm and was known as Pher i Porten ('Per of the Gate'), thereby explaining the patronymic as well as the other well known name of Agda: her parentage has, however, not been verified.
It was at that time customary for a Prince to have a mistress, though it was expected of him to dispose of her when he married by providing her with a pension of property or marriage.
On 25 August 1560, Agda was awarded the royal estate Eknaholm outside Växjö, which had belonged to a monastery prior to the Swedish Reformation, and which was to be her pension after the departure of Eric to England.
[1] This was in fact an illegal act, as the law secured the mother full custody of her children until the age of three.
However, if this is correct, this time the relationship was not official, nor exclusive: between 1561 and 1565, king Eric had a collective of mistresses referred to as Frillohopen ('The Crowd of Mistresses') consisting of Anna Larsdotter, Karin Jacobsdotter, Karin Pedersdotter, Sigrid Nilsdotter, Doredi Valentinsdotter as well as the anonymous Britta and Ingrid.