[quote=Rare]
Portugal could be a good nation to start.
[/quote]

It's not too bad, but I did a little reading and it looks like Portugal was in a state of constant decline at around this time. Their leader at around this time, Louis I, was not a very good... leader. It sounds like he didn't really know how to rule effectively. I didn't read anything that suggested he was a total fuck-up, but everything suggests he was a 'meh' leader that ruled during a time of decline for Portugal.

That is not to say you couldn't switch things around, but it'll be hard.