The Praetorian Guard

On the Gemma Augustea cameo (10x23 cm; 10 C.E.) The Scorpio of Tiberius is engraved on a shield which is exhibited at the Vienna Kunsthistorishes Museum.

Scorpio was the emblem of the Praetorian of bodyguards.
It was used to honor the Emperor Tiberius for building the Praetorian Camp in Rome. His birth sign was Scorpio.

From: http://www.redrampant.com/roma/vexillum.html

In 31 BCE Augustus founded The Praetorian Guard in order to prevent incidences like the murdering of Julius Caesar. Scorpio appears on many Praetorian items. The Praetorian Guard existed until 312 CE.

P.S.


Andrew From www.redrampant.com sent me this coin with the following explanation:

A Roman coin issued by the emperor, Galba. You can see a picture of the emperor addressing his praetorians. In the middle there is a shield with the Scorpio.

Besides, Tiberius built the city of Tiberias, which is called after him, and which has a Synagogue with a Zodiac (probably to honor Tiberius). Now, Tiberius is called after the Tiber river in Rome. I can imagine him watching the Sea of Galilee from his porch, feeling at home (as if he's watching the Tiber).