Llywelyn ab Iorwerth, also known as Llywelyn the Great, was a medieval Welsh ruler. He succeeded his uncle, Dafydd ab Owain Gwynedd, as King of Gwynedd in 1195. By a combination of war and diplomacy he dominated Wales for 45 years.

Joan, Lady of Wales and Lady of Snowdon, also known by her Welsh name often written as Siwan was the illegitimate daughter of King John of England, and was the wife of Llywelyn the Great, Prince of Wales, effective ruler of all of Wales. Joan or Siwan in Welsh has been referred to as both "Lady of Wales" and "Princess of Wales".