During a visit on Monday, a restorer in blue rubber gloves stood on a metal scaffold and took s a small paint brush to the dark clothing of a Byzantine Madonna on the walk of the church experts refer to as the Sistine Chapel of the seventh century.

The restoration project aimed at bringing the medieval frescoes back to their early glory has been under way since 2001.

The small church, built between imperial Roman palaces, is considered the most important Christian monument in the Forum.

The works is expected to be completed by the end of 2013.