For a long time, I thought this achievement would be really difficult (mostly because you'd need to take Hüdavendigar and Constantinople from the Ottomans, who seem invincible). Then one day I was watching a BudgetMonk119 video where he exploited a game mechanic to wreck the Ottomans while playing as Trebizond. I figured, if he can do it as Trebizond, then I should be able to do it as Aragon. This guide will explain how to play the first 10 years of the campaign, and to take Hüdavendigar & Constantinople within that first decade. Once you have those two centers of trade, the rest of the achievement will seem pretty easy.

To summarize, you need to start the game as Aragon, and you need these provinces.

If you'd rather watch a video than read the guide, that works too.

First, start the game as Aragon and pick any allies that make sense for you. In my most recent game I managed to get Castile, Austria, & Poland, but one of the key tenants of this strategy is to prevent the Ottomans from getting big early in the game by taking Constantinople before they can. Any alliance you can get to deter the Ottomans from attacking you will be good enough.

Next, there should be a scripted level 2 Stability Cost advisor to hire. By scripted I mean half price, and you can hire the advisor for a nominal amount like 5 ducats.

Militarily, you start off in a good position. You get a two star general with a siege pip and a two star admiral, a decent navy, and 17k troops. Don't worry about training up more land troops. You won't need more than 17k for about 10 years. What you will need is a larger navy, and don't be afraid to go over your naval force limit. You will need 17 transports, and as many galleys as you want. It should take about one year to build the ships. Send your whole navy to Spain, assign the general to your 17k stack, and send that navy to the Sea of Marmara.

Once you're army & navy are in the Sea of Marmara, declare a no CB war against Byzantium. In the recent patches they reliably ally Serbia, but nobody else. I've never seen Serbia or Byzantium get military access through the Ottoman territory, which means Byzantine, Athenian, and Serbian troops will be separated and easy to snipe off. I'd recommend attacking Constantinople first, then sending your army to attack Athens, then once the sieges are finished sending your fleet to Zeta to attack Serbia. This may take a while, but you have plenty of time and you want your Aggressive Expansion to wear down.

From Serbia, I would recommend taking Zeta. You can take more if you want to deal with the rebels and you feel it works for you, but Zeta is important because it allows you to fabricate claims in the Adriatic, and you need Dubrovnik and Venezia to get the achievement.

There are several ways to make peace with Byzantium, but whatever you do make sure that Constantinople does not fall into Ottoman hands. On one end of the spectrum you could full annex Byzantium for about 70 AE (and subsequently release them as a vassal to gain a Reconquest CB against the Ottomans). Or you could simply take Constantinople and leave the rump state of Byzantium and Athens to fend for themselves. You could even take Constantinople and force them to release Morea and Achaea as independent nations, then release Byzantium as a vassal if you want to get minimal AE. But AE really isn't an issue given the geography, even if you full annex Byzantium for the maximum AE, no nation will be willing to join a coalition against you.

If you manage to force vassalize Byzantium while they are the defender in a war against the Ottomans, you will become the defender in the war and you can call in your allies. However, I believe Paradox made this significantly more difficult since RadioRes used this strategy so effectively in his Aragon Phenomenon playlist. That may be possible if one leaves their army in Athens to make Morea and Achaea look available to the Ottomans. Something to think about.

Now with Constantinople under your control, you can take the rest of the Mediterranean centers of trade piecemeal without worrying about the Ottomans much. Maybe wait 10 or 15 years for things to get more stable, you can really take your time from here on out. If you're really lucky the Renaissance will spawn in Sicily, but if not no big deal.

Here are some tips for the rest of the campaign:

When I played as Aragon, and the Iberian Wedding event fired, it was Aragon who got to lead the PU over Castile. I assume this means the human player always leads the PU, whether Aragon or Castile.

What you'll need to know about the other centers of trade:

Genoa - it will be difficult to attack directly until 1490 since Genoa is in the HRE, but you could attack Genoa's ally if they have a weak ally. If you ally France, your ally should be able to pulverize Genoa. Don't wait too long though - you wouldn't want your best friend France to take Genoa for themselves.

Venezia - nobody will shed any tears if you attack Venice. You might even be able to get Austria or Hungary to help you. If Venice allies your ally France, then just attack one of Venice's allies.

Naples - you'll get this as soon as you annex Naples. I'm 110% certain you can do this before 1821. I believe in you.

Thesaloniki - I honestly don't remember this being part of the achievement when I got this in version 1.19. This might have been added in the Mandate of Heaven or Hungary patch. All you have to do is get some powerful European allies and eventually wreck the Ottomans again. The Ottomans' growth will be stunted once they never get Constantinople and lose Hüdavendigar, so they'll stagnate much earlier than they normally would.

Ragusa - they are guaranteed by the Ottomans, and they are usually smart enough not to get other allies. Maybe if they are in a trade league, you can declare war on someone else and take Ragusa in the process. Or when you want to take Thesaloniki later, you can attack Ragusa, beat the Ottomans, and take both provinces in one war.

Constantinople - Congratulations. Every ruler in this city since Constantine in 306 AD was granted the title Emperor of the Romans by the Patriarch of the Eastern Orthodox Church, and in real life Mehmed Osmanoglu was no exception. In this alternate history, you've taken that title for Aragon instead.

València - this is your capital.

Hüdavendigar - the Ottomans will not grow as much without getting City of the World's Desire. They will stall out much earlier than they usually do, and you can finish them off at your own pace.

Tlemcen - like stealing candy from a baby.

Tunis - like stealing candy from a toddler.

Tripoli - like stealing candy from that same toddler twice.

Alexandria - like stealing candy from an even bigger toddler. Just make sure you get there before the Ottomans do. Otherwise it's like stealing candy from the big toddler and the toddler's Dad shows up, and it turns out the toddler's dad is The Hulk.

I originally wrote this guide for version 1.20, and in that version of the game the Ottomans would attack Albania and commit 100% of their armies to that war. That would enable players to declare a no CB war against the Ottomans, quickly get a beachhead in Biga, and prevent the Ottomans from crossing back to Anatolia as long as naval superiority in the Sea of Marmara was maintained. Unfortunately, this strategy no longer works - the AI is a bit smarter now. But for old time's sake, here are some screenshots from that version of the guide.

Home and Away - v 1.28

Komnenoi Empire v 1.22

Mare Nostrum v 1.20

Georgia on My Mind v 1.18

This is Persia! v 1.18

Traditional Player v 1.18

We Bled For This v 1.18

A Blessed Nation v 1.18