HRH Prince Charles was created The Prince of Wales on July 26th 1958, at the age of nine. However his mother, HM Queen Elizabeth II, decided Prince Charles should not be invested until he truly understood the weight of his responsibility as Prince of Wales. At the age of 20, and after learning the Welsh language, as well as Welsh culture, Prince Charles was invested at Caernarfon Castle on 1st July 1969. The four stamps feature photographs that were taken during the investiture ceremony. 76p - Prince Charles arrives at Caernarfon Castle at the start of the investiture ceremony. He was accompanied by the Royal Family and Princess Anne is seen in the background. 82p - HM Queen Elizabeth II places the coronet on the head of Prince Charles. 94p - HM Queen Elizabeth II and the Prince of Wales stand at Queen Eleanor's Gate, Caernarfon Castle. £1.12 - HM Queen Elizabeth II and the Prince of Wales walk together on the grounds of Caernarfon Castle. The Miniature Sheet features Prince Charles' official investiture portrait, in which he is dressed in his investiture regalia. It also features some of his speech that he gave at hia investiture.