Just tried out the Lion Rampant rules by Daniel Mersey with my son.

Lion Rampant is a set of simple miniature wargaming rules designed for fighting historical or Hollywood battles in the medieval period, from the rise of the Normans to the Hundred Years’ War and beyond. Beyond means for us we wanted to use it in a Game of Thrones  setting. It works a treat for that purpose I have to say. The reason for that is that there are no hard army lists in the rules . All in all the rules are very easy to learn and use and give a very neat game experience. Recommended for people wanting a quick game without a ton of lists and rules for every possible situation.

We are only waiting for this to incorporate the Targaryen Dragons!