This whole story, about Venus and Mars, and a shield as a mirror was interesting, of course ( I hope), but it could be also easily not understood (or mis-understood) by a contemporary person modern man (I actually think it was already very difficult to understand even at the time of Tintoretto, in the 16th century) .
These difficulties are related to the very concept of a ‘shield’, which is completely alien to modern. We can understand (still mostly theoretically) the concept of a spear’ (or a ‘sword’), but the ‘shield’ lost nearly all it meaning. It’s basically perceived as some sort of ‘armor’ (like an ‘armored vest’) that is carried, rather passively, and that can protect its bearer simply because it’s thick and solid.
I myself was able to somehow regain the ‘work of shield’ only when I got some lessons of aikido; some of the explanations of the aikido explicitly refer to this dynamic dyad, of a spear/sword, and a shield, in order to understand the principles of movements called irimi and tenkan:
Irimi can be understood as an attack, a spear moving forward, a first of the right hand (of right-handed people, that is) that is trying to hit. Tenkan is a reflection, or rather, an evasion, but with a twist of your body that allows you to turn the energy of the attacker against himself (there is an inevitable reference here to the yin-yang dualism).
The main thing here is that the ‘shield’ does not as a passive barrier to the applied impact, but instead actively participates in the energy conversion (in case of aikido – by creating all sorts of different pivotal points, to lever and twists the body of the attacker around them).
I do not want to say that the ancient Greeks studied the techniques of Morihei Ueshiba, but I do know that the skills of handling the shield had been taught very seriously; it was as important as the skills of working with swords, or daggers, of axes, or any other attacking weapons. Of course, with time it has been mostly lost.
The reference to this active, deflective role of shields can be found in the story of Medusa (and its sad demise).
The biography Medusa was very complicated and full of gender abuses, how it’s called now; sufficient to say that she had snakes instead of hair. Among the enemies she had Pallas Athena herself (and it was Athena who, at the end, has helped Perseus to kill Medusa, giving him a special shield with a reflective surface).
René-Antoine Houasse – Minerva Presents a Shield to Perseus with Whom He Must Fight the Medusa (1690)
Here the artist has called Athena in a Roman manner, Minerva. The essence does not depend on rebranding.
Perseus also got many other valuable things from various stakeholders, but it was the shield that helped him to defeat Medusa – it allowed him not to look at the monster, whose gaze was turning every living creature to stone. During the battle of Perseus was looking at her through the mirror-shield and somehow managed to kill the poor woman.
Perseus killing Medusa, marble sarcophagus from Pécs-Aranyhegy (Hungary), mid 2nd c. BC
The engraving below, by a French artist of mid-18th century shows the shield that has a reflection of Medusa; this is, of course, a wishful thinking, because technically speaking the Greeks could only make bronze mirrors, and in the best case Perseus could see only a general silhouette (perhaps enough to fight, but not good to spot the nuances of the faces, for example).
It is also curious that Medusa didn’t turn into stone herself, while looking at herself in this shield-mirror! It shows that the Greeks somehow didn’t get the principles of mirrors’ work.
Lunette Depicting Perseus Slaying the Medusa, from the “Camerino” (1596)
On this painting the shield gradually transforms into a kind of convex mirror:
Francesco Maffei – Perseus cutting off Medusa’s head (1650)
When Perseus killed Medusa, he soon figured out that even while dead, her head still had the capacity to petrify the living beings..
and began to actively use it against his enemies
Luca Giordano – Perseus turning Phineus and his followers to stone (1680)
or to defeat the sea monster during his rescuing of Andromeda:
Piero di Cosimo – Perseus frees Andromeda (c. 1515)
On this famous painting by Rubens Perseus is depicted with a shield with an embedded head of Medusa, a very smart interface solution (but a bit dangerous too, on this painting half of the angels should be dead by now, and the Pegasus too).
Peter Paul Rubens – Perseus and Andromeda (1621)
In some versions the shield was made not for Perseus, but for Athena herself, whom the hero presented the head of Medusa at some point.
In the mind of the modern man this artifact is most likely associated with the work by Caravaggio:
Michelangelo Merisi aka Caravaggio – The ceremonial shield portraying Medusa’s Head (1600)
Or – in some pop-art icon – with the Versace brand:
In fact, what Athena eventually made from the head of Medusa was not a shield, but a so-called aegis, a chest armor.
This armor was later allegedly reproduced by Alexander the Great, who considered himself a descendant of Zeus.
This is only a small snippet from the large story about the shields; I will need to write more (and do more research for the next sequels).