They'll be much the same size, I imagine, and both horned, so they should be fine. As jaykay says, introduce them in a small space at first so they can't get a good run at each other. We used to do it in stages - first crammed together (using a hurdle) for half an hour or so, so they start to get used to each other's smell, then give them room to turn around and have a proper sniff, but not room to ram each other, then maybe 6' square-ish, then, (always assuming they are settled each time you increase the space) 10' x 4' (room to make a bit of a run, but a corner the weaker one can hide his head in), then a small paddock or pen. And not near the ladies for any of this, until they are settled as friends.