Hi, Patrick, I read the article which you provided on Queen Isabella, but did not find any indication of a policy of forced conversions of anyone whatsoever.
Let it go.
The point is that Catholic monarchies had plenty of severe shortcomings. (Find your own documentary proof.)
The point is that Catholic monarchies were bad enough centuries ago but nowadays they are not only unthinkable but also completely unworkable.
The point is that we should stop chasing after historical pipe-dreams and focus on the here and now with all of the practical constraints which render a Catholic monarchy impossible to re-establish anywhere other than someplace like Andorra or Leichtenstein.
The point is that rather than trying to impose Catholic values and morals through government (to whatever extent that's possible), we should focus instead on the interior - on personal holiness - and on . That is the ONLY way the world will change. We don't need a Catholic governemnt to have a strong and vibrant Church. The early Church thrived under an imperial government which was murderously hostile. After WWII, the Church thrived under Stalinist and post-Stalinist Soviet occupation. So why do we need a Catholic government?
Finally, the only thing a "Catholic" government can do is tarnish the reputation of our Holy Faith while accomplishing little else. Are you so unhappy and frustrated with the world and the state of most catholics that you feel we must resort to coercion to bring people around? That's not right. Don't you see this? Rejoice that the world and our secular governments are strongly at odds with the faith. This is how Jesus told us it would be. He didn't promise us a cakewalk, he called us to be saints in the midst of an evil and hostile world.