Prince Charles is the latest in a long line of heirs to the British throne who have enjoyed the title of Prince of Wales. Until the early middle ages, it was rare that any one leader could claim to have united the nation under one banner and become a Prince of Wales in its entirety, with the exception of rulers like Hywel Dda and Llywelyn ab Iorwerth.Edward I, the English King who, in 1282, finally completed the conquest of Wales begun 200 years earlier, gave the title Prince of Wales to his infant son, Prince Edward, in 1301.

Since then, the eldest son of the reigning monarch has been made Prince of Wales. (Daughters of the reigning monarch do not become Princess of Wales, as it is only given to a male heir). The only exception was the famous Welsh rebel Owain Glyndŵr, who was porcliamed Prince of Wales in 1400. The title isn't automatic, however. It has to be created each time by the reigning monarch - and as such is not an hereditary title. The first official Prince of Wales, the infant future King Edward II, was born in Caernarfon Castle in North Wales, and in 1911, the future Edward VIII was invested with the title in a ceremony in the same castle, the first time such a ceremony had taken place in Wales. At the age of 18, Prince Charles was also invested with the title in Caernarfon in 1969.

Prince of Wales' Standard
The Prince of Wales has three standards or banners - his personal standard, a standard for Wales and a standard for Scotland. In 1962 the Duke of Edinburgh suggested that the Prince of Wales should have his own flag after his investiture exclusively for use during visits to Wales. The Queen gave her approval. The standard, which was devised by the College of Arms, is based on the arms of the principality of Wales, also known as the arms of Llewelyn ap Gruffydd, the last prince of Wales before its conquest by Edward I.

The design bears a similarity to that borne by Owain Glyndwr during his rebellion against the English. Significantly, the more recent design has an English crown added to the centre. The flag was first flown on 11 June 1969 - three weeks before the prince's investiture - at Castle Green in, Cardiff. The event was the inauguration of the Royal Regiment of Wales, of which the prince is colonel-in-chief. During the investiture ceremony on 1 July 1969, the standard for Wales was flown from Caernarfon Castle's Eagle Tower.

The standard is also known as The Prince of Wales' Personal Flag for use in Wales. In 1999 Buckingham Palace agreed to fly the Prince of Wales' flag alongside the Queen's at the official opening of the new Welsh Assembly. The change of heart meant the Royal Standard - the Queen's own flag - was flown alongside with that of Prince Charles's for the first time in living memory. Each member of the Royal Family has an official flag, which is flown to denote their presence. By convention only the most senior member's flag can be hoisted. But efforts were made to break with protocol and raise the flags together, for the first time in 400 years.

Source:http://www.bbc.co.uk