A Cornish MP has asked the government to make 5 March a public holiday in Cornwall to recognise celebrations for St Piran's Day.
St Piran's Day is marked by a march across the dunes at Perranporth
In a Commons early day motion Lib Dem Dan Rogerson said a public holiday would be a "valuable opportunity" to celebrate Cornwall's unique heritage.
St Piran is said to be the patron saint of tin miners who at one time had a booming industry in the county.
Earlier calls to mark St David's Day, 1 March, were rejected by ministers.
Mr Rogerson said in the Commons: "The celebrations of Cornwall's patron, St Piran, on 5 March each year are growing in scope, support and significance."
He said it would be a "valuable opportunity" for the people of the county to celebrate their "unique heritage, language culture and aspirations".
It is thought St Piran arrived in Cornwall at Perranporth, where he founded his first church and monastery in the sand hills at Perranzabuloe.
The ancient church on the dunes near Perranporth is believed to be one of the oldest sites of Christian worship in the British Isles.
His feast day is marked by a march across the dunes at Perranporth, where St Piran is said to have come ashore in the 6th Century, having made the journey from Ireland in a currach.
The Cornish flag is known as St Piran's Cross, a white cross over a black background.
It is said to symbolise the Christian faith shining over lies, good over evil, although some believe the flag represents white tin coming from black rock.
Mr Rogerson's motion is supported by the county's other four MPs, all Lib Dems; Colin Breed (Cornwall SE), Andrew George (St Ives), Julia Goldsworthy (Falmouth and Camborne) and Matthew Taylor (Truro and St Austell).