Quote from the Oxford Dictionary:

opus sectile (Latin: ‘cut work’). An inlaid design made of pieces of marble that are individually shaped to fit the pattern or picture, as distinct from mosaic, where the design is built up from countless small pieces (tesserae) of stone or glass. It is a rarer and more luxurious art than mosaic, since the plates of marble are larger, more fragile, and more precious than tesserae; and it was in Egypt and Asia Minor, lands rich in coloured marble, that it had its origin. The Book of Esther (1: 6) describes ‘a pavement of red and blue and white and black marble’ in the palace of Ahasuerus (probably to be identified with the Persian king Xerxes I). However, little survives from before the time of the Romans, who used opus sectile extensively for wall and floor decoration. It was later used in Early Christian and Byzantine churches, and evolved into more specialized crafts such as Cosmati work. Geometrical opus sectile continued to be popular in Italy for decorating church floors throughout the Middle Ages and Renaissance.

The Long Tower Opus Sectile:

These are the three grand panels behind the high altar – the Ascension of Christ flanked by St Peter and St Paul. These magnificent works were installed in 1909 and have not had any significant repair since then. Deterioration has accelerated over the years and they had got into a very advanced state of disrepair. Looking from the pews one could not observe the wear and tear but a closer inspection would show that the tiles were collapsing into one another. A recent expert survey had declared the panels “dangerous and in urgent need of repair”.

Opus Sectile (pronounced “seck-teel-ay”) is the Latin name, and the modern technical designation, for a series of opalescent painted glass tiles, first used by the ancient Romans on luxury floors. Meaning “cut work”, just like stained glass or coloured glass the individual pieces have been fired in the kiln. Usually these glass sections are set in grout and there are many such examples around the inner walls of Long Tower. However what is distinct about the panels above the tabernacle is that they are set in lead, like stained glass windows. The experts say this is extremely rare and sets these particular panels apart as remarkable works of art.

The repair was extremely specialised work and had been under preparation for many months. It could not be done on site therefore the three large panels had to be taken away to studios in Belfast. In the intervening months we installed three photographic replicas of the panels so as not to take from the aesthetics of the church. We had to install some temporary scaffolding and protective hoarding for the purpose.

The project cost is over £20,000 to complete. Thank you for your generosity in supporting such necessary repairs and for your patience as they happened.

Unveiling of The Long Tower Opus Sectile:

Monday 9th March 2009

10.30am UNVEILING OF THE OPUS SECTILE

On Monday morning there was a formal unveiling of the restored opus sectile in Long Tower. These are the three grand panels behind the high altar – the Ascension of Christ flanked by St Peter and St Paul. Opus sectile (pronounced “seck-teel-ay”) is the Latin name for a series of opalescent painted glass “tiles”, first used by the ancient Romans on luxury floors. Usually these glass sections are set in grout and there are many such examples around the inner walls of Long Tower. However what is distinct about the panels above the tabernacle is that they are set in lead. The experts say this is extremely rare and sets these particular panels apart as remarkable works of art.

The repair was extremely specialised work and has been done in studios in Belfast. It involved putting supplementary metal bars and additional wire ties into the three frames. Since lead is a high expansion material the restoration required re-gauging the glass and the lead to give the material space for expansion. The three magnificent opus sectile panels will be unveiled and blessed tomorrow, Monday after 10.00am Mass, to honour the 9th day of the month, St Columba having died on the 9th of June.
The project costs over £20,000 to complete. To help us fund the restoration we are selling pictures of the masterpiece. The mounted pictures will be available for purchase from the Long Tower Church and the Parochial House, costing £19.95 or £45. Please note that this does not include a frame. You might consider it to be your own memento of the 100th year of Long Tower. The proceeds go towards the cost of the repairs and the general restoration of the Long Tower.