I posted this earlier:
from Wikipedia:https://en.wikipedia.org/wiki/Column_of_Antoninus_Pius
"
One side of the base has a dedicatory inscription (CIL vi.1004), two sides record the funerary decursio or decursus (a ceremony performed by the Roman cavalry), and one side shows the apotheosis or ascent to the gods of the emperor and his wife . "
17 Cavalry are in the procession of each Decursio,
From Wikipedia
"Decursio
On these two almost identical sides, members of the cavalry circle the standing figures, two carrying military standards and the rest fully armored. Lacking a sense of space and perspective, these scenes are often criticized for their lack of stylistic sophistication. Instead of naturalism, both a bird's eye view of the circular manoeuvre and a ground-level view of each figure are provided. The repetition of the scenes can best be explained by the fact that Antoninus Pius was succeeded by two emperors, Marcus Aurelius and Lucius Verus, who reigned jointly until the latter died. The decursio depictions, as well as the language on the inscription, can be taken to show a stable and justified transition to the two co-rulers. "