The world has been fascinated by the discovery that a marble trough being used as part of a rockery at Blenheim Palace, on the edge of Woodstock in Oxfordshire, has turned out to be the remains of a 1,700-year-old Roman sarcophagus that has been valued at £300,000 following its restoration by Cliveden Conservation.

The remnant of the sarcophagus had been used first as a water feature and then as a flowerpot as part of a rock garden at Blenheim Palace since it was obtained by the 5^th Duke of Marlborough sometime in the 19^th century. It was initially used to collect water from a natural spring on the Oxfordshire World Heritage site. Now, fully restored, it has been put on public display inside the palace.

Following thorough investigation, it was identified as the front of a white marble sarcophagus. It is covered with fine bas-relief carvings depicting a drunken Dionysus leaning on a satyr flanked by party revellers including Hercules and Ariadne. There are also two large lion heads.

A team of conservators from Cliveden Conservation was brought in to carefully lift the marble section out of the rock garden after it had been identified as a rare piece by an expert brought in to value some of the treasures at the palace. It is close to two metres long and weighs more than 400kg. Cliveden took it to the company workshop near Maidenhead, Buckinghamshire, to be gently cleaned and carefully restored.

Nicholas Barnfield, who oversaw the restoration, said: "The piece is actually in remarkable condition considering it has withstood seemingly aggressive environments; particularly that of a fountain receptacle.

“Following an initial in-situ inspection we were able to unbolt it from the lead cistern to which it was attached and take it back to our workshops for full cleaning, repair and stabilisation."

Nicholas and his team safely returned the restored marble fragment back to Blenheim Palace for it to be put on public display inside the palace. Kate Ballenger, House Manager at Blenheim Palace, says: "We are delighted to have it back and the restoration work undertaken by Nicholas is very impressive.

"Now it is in a consistent indoor climate away from the natural elements we are hoping it will remain in good condition and survive for many more centuries to come."