That is a statue of Arash the archer from the the folklore but the name has its roots in the Parthian era and they were one of the best horsemen to ride out of the steppe. They were one of the 1st horse people to breed a large horse that had speed strength and stamina to carry a fully armoured horseman and the horse was also armoured. These elite horsemen became what we call knights or chevalier in French.
They had a code and were chosen from families with noble blood. At the battle of Carrhae a force of light cavalry archers and heavy Parthain cataract decimated a numerically superior Roman Army with very little losses.
The saying "parthian shot" comes from the way parthians would fire arrows as the galloped towards the enemy but also as the galloped away drawing the enemy into traps.
It is believed that it was such peoples as them that inspired the legends of the centaurs.
I am also of nomadic extraction and my forefathers come from the same region and had/have a similar way of life, hence why I feel more attachment to mounted archers than foot ones.
Here endeth the lesson

Further reading for you:
http://en.wikipedia.org/wiki/Parthian_Empire