On 15 July 1823, the Basilica of St. Paul’s Outside the Walls was almost destroyed by fire.
The basilica, one of the five major basilicas of Rome, was originally built by Constantine I atop the site of the execution of Saint Paul, but was modified throughout its long history. From 1215-1964, it was the see of the Latin Patriarch of Alexandria.
The fire was apparently caused by worker negligence during repair of the roof. Workers were soldering the lead roof when burning coals from from a brazier used to melt the solder fell on the roof. Most of the basilica was destroyed including almost all of the paintings of the pontiffs which lined the basilica’s walls.
The Basilica would be repaired and reconsecrated in 1855 by Pope Pius IX and fifty cardinals whose names can be seen inside the basilica. Many countries would send materials for the reconstruction, including the Emperor of Russia Nicholas I who sent malachite and lapis lazuli for the tabernacle. So, while most of what can be seen at the Basilica today is modern but the repairs did attempt to use original materials and the original design of the basilica.
A print of the fire damaged basilica can be found here.