Obviously you would raise an army to invade Random House and force them to recognize your claim. If you yourself don't have the funds to hire a sufficient numbe

Obviously you would raise an army to invade Random House and force them to recognize your claim. If you yourself don't have the funds to hire a sufficient number of mercenaries, what you'd have to do is find a local patron and convince them that they should support you for various reasons. Most likely in this case, you'd have to promise them a significant share of the royalties. Assuming you manage to convince your patron(s), they would then assemble their army and fight Random House's army. If successful on the battlefield, congratulations! I can already feel the Liberty.