Previous digs within the park uncovered the remain of a Roman fort
A team of archaeologists is hoping to solve a centuries-old mystery and discover the remains of two medieval ancient towns in Carmarthenshire.
The settlements are believed to be within the grounds of Dinefwr Park and Castle near Llandeilo.
Their existence is recorded in several medieval documents and researchers are hoping to pinpoint the exact locations later this month.
Previous digs in the grounds have found the remains of a Roman fort.
Archaeologist Emma Plunkett-Dillon said: "We know that the two towns existed because they were well-recorded in various medieval documents.
"We know that there was a Welsh town somewhere around the castle and an English town nearer the present site of Newton House, in the centre of the estate.
"Records kept by the Crown show us that they were occupied throughout the 14th and 15th centuries - we even know how much rent people who lived there were paying at the time - but the towns themselves have completely disappeared."
The Welsh town was settled by the indigenous population sometime after 1277 when Dinefwr Castle was under Welsh control.
What is referred to as the English town was established some time after that time, in order to colonise the area and capture the castle and surrounding area for English control.
Work will begin to try and pinpoint the exact location of these towns, beginning with the English one, on 23 June.
A team from Dyfed Archaeological Trust together with a group of volunteers will undertake a geophysical study of the land surrounding Newton House.
A machine will pass over the ground, detecting changes within the soil that will enable the archaeologists to identify buildings and other features buried beneath the grass.
This will be followed by the excavation of a series of small pits which hopefully will clarify the nature of the buried archaeology.
"I don't want to raise expectations, but potentially this could be an extremely exciting investigation," added Ms Plunkett-Dillon.
"I've been working at Dinefwr myself for almost 20 years and have never seen any signs of these towns.
"This is a golden opportunity to try and find them - what we're actually doing is lifting the lid and taking a look at previously unexplored areas and I for one would dearly love to finally find something."
The public will have an opportunity to watch the archaeologists in action during an open day on 28 June.