Are you sure it is a Star of David? It is a Christian basilica; my wife says it's impossible it is a Star of David. Ciao.
Well, I’m not sure, but it is a six pointed star made of two equilateral triangles just the same as the Israeli national emblem. I think it might belong to the Jews of Aquilea because:
If you’ll read Samuel Kurinsky’s article - titled “The Jews of Aquilea A Judaic Community Lost to History”- you’ll see that there was at the first centuries CE a Jewish community in Aquileia...
The white lily motif in the center of the star appears also in Ein Yael in south Jerusalem in a farm with a Roman villa from mid-third-century A.D. (from the same period as ours).
In 1981 Professor Eric Myers of Duke University found in Villa Torlonia in Rome a series of Jewish catacombs, which were in use since the first century CE. several of them show a six-pointed star.