But crosses of this sort were known all throughout the Roman Empire as symbols of victory; because they were used as the frames of tropaea (trophies).
1) Here is the Roman Goddess Victoria next to a bound slave, kneeling under a tropaeum; its shields give away the shape of the frame--the shape of a cross.
2) Here on Trajan's Column is a relief representing a tropaeum decorated with enemy armor. Note again, the typical form of the tropaeum is in the shape of a cross.
3) Here in the lower left-hand corner of the Gemma Augustea is a victory party of Roman Soldiers exalting aloft a cruciform tropaeum. Note the bound slaves by its foot.
5) And here are the reenactors of the 8th Legion Augustus with a vexilla; its frame's shape is that of a tropaeum.
6) Here is a Roman Eagle perched on top of its standard, which is shaped like a T. This unusual for a tropaeum.
8) Here is a coin of Augustus Caesar, on the reverse he is being anointed by the Roman goddess Victory with the star of Julius Caesar while holding a Nike (angel), portrayed roughly in the form of a tropaeum.
9) Here is a coin of Vespasian Caesar, minted by his son the Imperator Titus, showing on the reverse a tropaeum. Note that captives were always bound at the foot of the tropaeum.
10) And here is another coin of Vespasian, again minted by Titus, with an image of a tropeum, a bound captive kneeling at its foot.
11) And here on view at the Charlottenberg Museum in Berlin is a mini-tropaeum depicted wearing the body armor of a Roman Imperator or a Caesar, perhaps even Julius Caesar.
12) And finally here is a reenactment of the Funeral of Julius Caesar, with his likeness showing all twenty-three stab wounds mounted on a cross, or tropaeum.