A sacred staircase which Christ is said to have climbed to be sentenced to crucifixion by Pontius Pilate has been restored to its original state after nearly 300 years.

The 28 steps of the Scala Santa, or Holy Staircase, are believed to have been brought from Jerusalem to Rome in the fourth century AD by Helena, the mother of the Emperor Constantine, who adopted Christianity as the official religion of the Roman Empire.

The marble staircase had been encased in wood since 1723, when the pope of the time, Innocent XIII, decided that it could no longer stand the wear and tear of millions of pilgrims, who by tradition must crawl up it on their hands and knees to earn indulgences.

During a long restoration, the wooden planks were removed and the intricate 16th century frescoes on the walls and ceiling above the staircase cleaned and returned to their original lustre.

Restorers found inscriptions and graffiti scratched into the frescoes, including a message of thanks by one Italian man who had escaped being held as a slave by the Turks.