A close study of the painting shows that its history is very complex, denoting a sequence of several extensive restoration interventions. The last extensive intervention was undertaken in 1910-1912 by a prominent Maltese artist, Giuseppe Calì (1846-1930). In the late 1930s, under the governorship of Sir Charles Bonham-Carter, the vault was entirely whitewashed after being covered with varnish. In the 1980s the Museums Department started uncovering and restoring parts of the vault painting, such as the figure of Pallas, and in 2003, a conservation team from the former Malta Centre for Restoration uncovered the entire first bay depicting Bacchus and Mars.
Commenced in July 2006 by Heritage Malta, the conservation project, which has just been concluded, was intended to complete the uncovering of the vault painting and ensure the preservation of the more recent (1910-12) painting scheme. Besides the removal of the 1930s whitewash and the consolidation of the painting, the project entailed extensive historical and scientific research. Heritage Malta said laboratory studies and tests were also carried out on the possibility of removing the varnish which was applied prior to the whitewashing. Based on current information, it was not possible to arrive at a safe method to remove the varnish without damaging the underlying painting. The final stage of the fieldwork consisted in toning down the paint losses and abrasions using watercolours. This final treatment was undertaken with the intention of preserving the traces of colours that belong to earlier painting phases (e.g. the figure of Venus).
The investigations carried out so far have clearly indicated that this painting has an incredibly rich history, part of which has been revealed during the current conservation project. Over the next few months, Heritage Malta intends to pursue further research in order to tackle a number of questions that remain unanswered. In addition it plans to start an environmental monitoring campaign which will be essential for the long-term preservation of such a complex painting scheme.
The project was set up on the initiative of the President of Malta, Eddie Fenech Adami, and was financially supported with a sponsorship of e186,350 (Lm80,000) by Prof. Joe Bannister and Messrs. George Fenech, Joe Gasan and Charles Polidano of the Malta Services Authority, Tumas Group, Gasan Group and Polidano Brothers.