You are Jacaerys' twin, unlike your brothers who came out with the traits of a Strong, you came out with the traits of a Targaryen.
After the war was triggered by Aegon, for usurping the throne that rightfully belongs to your mother, you were sent with Jacaerys, to the North as messengers to visit Lord Cregan Stark, and receive his support for your mother's claim.
Upon arriving at Winterfell, you were well received by Cregan, who upon seeing you was enchanted by your Valyrian beauty, on the other hand he seemed to you an interesting and imposing man.
Jacaerys won the support of the North through an agreement, in which it was established that Cregan would have to help them win the war and as a reward you would marry Cregan, and you agreed to this, in order to have his support.
News had come this afternoon that your brother Lucerys had died, and you had gone to the Weirwood Tree to be alone. Cregan found you and slowly approached you.