A soldier from The Royal Welsh celebrating St David's Day on parade in 2008 (Picture: PA).
Dydd Gŵyl Dewi Hapus! It's the 1 March, and the people of Wales are celebrating St David.
This is a very important day for Welsh units, and particularly for the 1st Battalion Welsh Guards, who are commemorating the occasion at Lucknow Barracks.
But first of all, who is Saint David?
St David is the patron saint of Wales and doves. Born in Caerai, Pembrokeshire, the Christian missionary and archbishop was believed to be a nephew of King Arthur.
Later on, he founded a monastery where the area of St Davids stands today.
He is considered a symbol of Welsh resistance against the Norman Conquest and has been the patron saint of Wales since the 12th century.
Why do Welsh units wear leeks?
According to the legend, when the Welsh fought the Saxons they were both wearing similar uniforms.
St David then advised the soldiers to wear leeks on their caps to distinguish themselves.
In the end, the Welsh won the battle, and the leeks have become a symbol ever since, also helped by Shakespeare's representation of Fluellen in 'Henry V'.
Although presented with leeks for the occasion, Welsh soldiers carry the emblem every day, as they show the symbol on their buttons.
How do the military celebrate it?
While civilians limit themselves to sporting daffodils and taking part in festivities across the country, Welsh units tie leeks to their caps or helmets. However, the Royal Welsh have a more specific tradition... Eating them.
The infamous 'leek eating ceremony' sees some brave soldiers munch their way through a whole raw leek!