Vexilium of The Senatus Populusue Martius (Senate and Martian People).
from /r/vexillology Top comment: A vexilium I threw together for a fictional (clearly) Martian Republic built on the ole Mars being an independent and aggressive entity cliche. I took the oh so creative route by making Mars into a new Roman style republic, but based more around the cult of Mars itself rather than traditional roman trappings like eagles and such. Its a little busy with the laurels on either side of Mars, but the two separate designs show the two aspects associated with Roman Mars. While Ares of Greece is a bloodthirsty killer, Mars of Rome is a soldier's deity, a father god, and importantly a god of agriculture. Hence the laurel wreath (valor) and the wheat wreath (agriculture). Both would be important to Mars in defiance of Earth and making their planet flourish into a new home. Weird cult and political apparatus and martial...martians of mars....inspired by both Kim Stanley Robinson and The Expanse. Clearly.