To finish my Maltese question series before boarding a plane off the island, here is another question about Latin inscriptions in tombstones in St. John's co-cathedral at Valletta. In many tombs, including the one below, the inscription begins with the abbreviation "D. O. M." in a fashion very similar to Roman grave inscriptions starting with "D. M." much earlier.
What does this abbreviation mean? I did not find any graves with this abbreviation expanded (starting with three words with initial letters DOM). I assume it is a Christian counterpart of the Roman Dis Manibus and that the D stands for some form of Deus. Is "D. O. M." related to "D. M." at all, or is the similarity a complete coincidence?