What is required to ride a wild horse as a druid?

[Taku Ooka Nin]

So, this came up recently.
If my Druid uses call animal, uses wild empathy to make the animal like him like him and wants to ride said horse, what is required for that happen.
If I need to train the horse, what skill exactly do I need to teach it? I don't have a week of time to train it.

[Nefreet]

Also you need is the Ride skill.

Even wild mindless vermin can be ridden.

If the animal you're riding doesn't have the trick you want it to use, getting it to perform that trick requires a Handle Animal DC 25 (27 if injured) check using the appropriate action.