A remarkable piece of sculpture, certainly.
Nothing is always true, however.
Other lions serve merely as decorative elements, prowling thru the luxuriant vegetation of Romanesque scrollwork, as elsewhere in fact on this very Sarcophagus of Stilicho, or much like their modern cousins in le douanier Rousseau. Large eyes are common enough in sacred sculpture, but the particular type we see here, almond-shaped with a very prominent black pupil, looks very much to me like those of the Sumerian gods. Much of the art in this church of S. Ambrogio is either Byzantine or influenced by the Eastern Empire, very likely thru Venice. Just four years after this monument was built, Venice would in fact, to her shame, plunder Constantinople and make herself mistress of much of its artistic heritage. Now I warned you when we started, that I was probably wrong.