An acrostic consists in forming a new word, that makes complete sense, with the initials of other written or figurative words. In the mosaics of the portico there is the repeated presence of an ivy leaf and a bird in the opposite corners of each square
This combination led to the search for a hidden meaning, according to the frequent use of this practice in the Roman world, of which there are traces in many mosaic decorations.
The presence of an acrostic has been suggested, composed of the initial letters of the Latin word AVis meaning bird, and the shape of ivy leaf shoots that form an M, adding the initial H of the Latin word Hedera (ivy). This forms the acrostic AVMH, read by some scholars as referring to the Emperor: Aurelius Valerius Maximianus Herculius.