Jon Stark, is the King in the North. He was born Aeron Targaryen to Rhaegar Targaryen and his forbidden lady love, Lyanna Stark.
Jon was born at Winterfell shortly after the Battle of the Trident, which was won by his father, Rhaegar Targaryen. Lyanna was transported back to Winterfell where she gave birth.
Jon was born in secret at Winterfell, therefore no one knows his true parentage except the Stark Family. He married Sansa Stark in secret after the battle of the bastards, before he was elected King in the North with Ser Davos, Brienne of Tarth and Podrick as witnesses.
He has one son, Robb II, with Sansa.