What do the Denarius of Julius Caesar, Augustus of Primaporta, and Emperor Justinian and His Attendants have in common?

Propaganda, the Denarius of Julius Caesar, Augustus of Primaporta and Emperor Justinian and his attendants all serve a propaganda function.

Explanation:

The denarius of Julius Caesar was the first time the portrait of a living person was featured on a coin. It shows a profile of Caesar on the front side and Venus on the reverse side. It was used as propaganda to assert Caesar's claim of being descended from Venus.

Augustus of Primaporta sought to use the coinage as propaganda to normalize his image as an imperial leader, and serves an integral role in the success of his rule. It depicts Augustus as a holy man and employs many pagan symbols in respect to the Roman priesthood which he presided over.

The mosaic of Emperor Justinian shows Justinian as a ruler of the church and state, Justinian holds a gold plate which was his offering to the church in place of the communion bread. The propaganda function it serves was a way of showing people his presence in the church because a lot of people believe Justinian and his wife never even go to church.