Ancient sidesaddles

I have some civilians wandering around the battle field, usually in the camp.
One of which I want to do a conversion is a female civilian riding side saddle. There is ample evidence that this was a form of riding by both woman and men in ancient Greece and Roman [and by Gods such as Epona ]. However since they didn't have stirrups I wonder about stability. One contemporary image shows a board under the riders feet which I assume is attached to a saddle by straps. Some medieval side saddles use the same technique which I am assuming followed the ancient pattern.
On the off chance has anyone any information on ancient side saddles?
B.

I've known a few modern side-saddlers. It's a skill that I've never tried (and it's not only for women, by the way).

There were two main types before the pommel brace of a modern side saddle.

The classical style was basically a chair harness that the woman sat in and was led around. There was a board as part of the equipment that allowed the passenger to rest her feet. The horse could not be controlled by the rider. This chair seems to have been cut down in size over the centuries. It was called a "sambue".

The second was the pillion. This was mostly medieval and was a two person job. The woman sat behind the "rider" on a shaped cushion. The only one I've seen looked like a thin bolster wrapped around a leather pillow. Once again, the woman could not ride on her own.

Possibly the more significant aspect is the horse. Led horses were much smaller. The most popular was the palfrey, a small and very biddable horse. Good luck with finding one as most horse modellers only seem to do thoroughbreds (which didn't exist) or destrier-styles (which also didn't exist). A big horse would have been twelve hands high. That's pony size. A palfrey would have been even smaller and lighter in frame.  

Here's a picture

Side saddle picture

Thanks for that. It was the 'sambue' I obviously had in mind but hadn't come across that name previously.
You reply was very helpful.
B.

Where can you find a history of the sambue? I have never heard of it before until I came across the mention of it in a book on the biography of Catherine de Medici, who is said to have introduced the side saddle into France. Is that true?

The book is Catherine De Medici, The Power Behind the French Throne by Barbara Sommervill.