 In the book "Prince Caspian", Caspian overthrows Miraz, with the help of the Old Narnians, to take his rightful position as King of Narnia.In "The Voyage of the Dawn Treader" he sets sail for the Lone Islands and beyond to look for the seven lords who had been sent to explore the lands beyond the Eastern Ocean.In chapter 5 they finally made it to the island Spaflin and found Lord Bern stuck in a wall.