* Safety: The left side is traditionally considered the "safe" side for mounting because most horses are trained to be ridden from the left side. This means they are more accustomed to having someone approach them on their left, and their left flank is often considered their "blind side" (the side they have less awareness of). By approaching from the left, you minimize the chance of startling the horse.
* Equipment: Most horse tack (saddles, bridles, etc.) is designed for left-handed mounting. The stirrups are typically positioned on the left side, and the saddle itself often has a slightly higher cantle (back) on the left side for easier mounting.
* Historical precedent: This tradition stems from the historical use of swords, where a right-handed rider would need to be able to easily draw their sword from the left side of their body while mounted.
While it's possible to mount a horse from the right side if the horse is well-trained, it's generally discouraged for safety reasons.
However, if you are a beginner or unsure, always ask the horse owner or your instructor for guidance. They can advise you on the best approach for the particular horse and situation.