Two 800-year-old gravestone slabs that went down with the ship transporting them in the 13th century have been recovered. One slab is intact and in excellent condition; the other is much larger but broken into two pieces. The slabs were brought to the surface in a complex operation requiring a barge anchored to the seabed, a crane and huge metal crates to raise the heavy Purbeck stone slabs.

The Mortar Wreck sank in Studland Bay off the coast of Dorset in the second half of the 13th century. Dendrochronological analysis of the hull planking found the clinker-built ship was made from oak trees cut down in Ireland between 1242-1265, when Henry III ruled England. It is the only known wreck of a seagoing vessel from the 11th to the 14th centuries in English waters, and the oldest known shipwreck in the seas surrounding the British Isles. (There are a few Roman wrecks but they were found inland.)

This was a period of prosperity when the population was booming and huge building projects like the construction of Westminster Abbey and Salisbury Cathedral were underway. The Purbeck quarrying and transport industry was at its peak during this time, and the gravestone slabs were very popular among the clerical elite. The ship was carrying a heavy load of unworked quarried Purbeck stone, the gravestone slabs, carved with cross decorations but not polished yet and not personalized, and a number of daily use objects including Purbeck stone mortars used for grinding flour, which is what the wreck was named after.

The wreck was discovered in 2019 by Bournemouth University divers. It was granted official protection in 2022, and maritime archaeologists have been monitoring it for condition and exposure as sediment erodes. The monitoring of the Mortar Wreck will continue. This includes a plan to document the timber frames of the ships hull. It will also be a learning site for students at the university to be trained in maritime archaeology.

The recovered slabs will be desalinated and conserved by Bournemouth University experts. They will go on public display at the Poole Museum in its new Shipwreck Gallery when it reopens next year.