Now I assume you found all 30, I've covered every one over the course of the walkthrough. So all you have to do is talk with Leonardo right here at the villa. Be sure to grab your coin from the chest.
I assume not having them all will require you to go out hunting for them. So just hit up each city, open the map, and if all viewpoints are found then all pages will be on the maps. You can filter the legend to show only these since that is all you want. Bring them to the villa for Leonardo to translate.
Go to the codex wall and insert your last two.
X Marks the Spot
Once you have all 30, speak with Mario.
Use eagle vision and if you haven't arranged them yet, they are meant to resemble a map of the world; if you have never seen a map of the world, I'm not helping you there.
The only tricky ones are the eastern coast of America, all of Europe, and Russia (pretty much all of the nothern hemisphere except Canada...) and the game will exit you from the puzzle when you have it all in order. Feel fre to rotate ones you aren't sure about.
Now insert the Apple into the pedestal in front of the map.
Clearly if you have any business to attend to, feel free to do so now. But you can also do them later if you want. I mean upgrades, purchases, that kind of stuff.
*NOTE: I took this time to find the glyphs, which are not an essential part of the game, but now you can get them all. And all of them are marked in your database under "Locations", the ones with eyes in the corner have glyphs. But if you want to see the end of the game more, the glyphs take a long time to hunt down, even just a few.*
*NOTE: If you didn't get the 8 statues in this villa before, you can do so now. You can use that section in this guide or just turn on eagle vision and try to find them yourself; they are easy to find.*
When ready, talk with Mario in his room.
In Bocca Al Lupo
Nope, don't get excited and think this is a brand new city. You are just in a portion of Rome and can't leave, so stick to the mission. This mission is a mega display of everything you've done in this game thus far.
Go up the left wall, then use the boards to get on the platform and then onto the wall ledges. From there, jump to the board holding up the platform, then go up and left. Leap up from here, then get up near the top.
You can't move along the top of this rail wall, but you can from the lower ledge line. Use it to take out both guys that look out from the railing. Then either leap from the rail to the pike guy, or run up behind him, or kill the first one and then just toss the pike guy off the tower.
Pull the lever on the wall, then let the two beyond the gate turn away from you so you can run up behind them both, squeeze between them, and instantly take out both with a double-hidden blade kill. Then run up the wall and pull down the other.
Pull the lever here and then same thing in the next area, only you have to try for the double kill and then engage in combat with the three left. Same as I always say, just counter kill them all with your blades. Then get on the marker.
Now you use a horse to advance along the wall, but you don't have to kill all the guards in your way, so just use your high profile, slow, and slash at enemies when you see a line form or they will knock you down. Doesn't matter if you do, just get on your steed again and try to advance while slashing away.
When you reach the locked gate, dismount and kill anyone near. Go up the tower, leap to get up, pull down one archer, then kill the other. Jump into the hay and get on top of the roof of a nearby shack to double kill two guards. Then just run up and double kill the two down the way.
Up the next tower, another leap up the wall, kill this archer. Leap to the hay when the patrol goes away, kill the guard near, run up to the next hay pile, and kill this pike guy as the patrol isn't looking. Then just run up to the pats and double kill, or at least target the back one first in case you don't get both and this way you can try to get both individually.
Up the tower pull down the first, then double kill the pair. Air kill the guard below and then kill the other from behind. From this tower you can see a group of four pats below, as well as a pair near the tower. It's hard to aerial kill the pair and then hide over the side wall to the right without being seen by the pats, but you have to leave when the pats are far away from the pair. Hanging over the wall, you objective is to sneak to the roof, and if not aerial kill some of the group, then maybe sneak to the lever. But most likely you'll have to fight them and some more. One good move is to retreat to the roof of the shack anyway to thin out the little guys, the big guys lose sight of you, aerial kill them, and then toss the pike guys around and kill them on the ground. Pull the lever up on the wall.
The action sequence is over, now to the stealth part. The first two are easy to kill. You can ignore the left guard and just kill the other one if you want, then pull the lever.
The thing to note is the monks scatter if they see you kill someone, but if they don't then you have nothing to worry about.
In the next part you have the first one on the left that can be killed easily. The patrolling guard needs to be poisoned on the left side of the dividing wall. Just stand way back as he goes into his rage of death. Let the pair by the lever re-establish their original positions, then creep behind the wall, come up behind them both, get in between, and double kill. Pull the lever.
Follow the boardway along the right wall to the platform over the Pope and take him out.
Well, not exactly. Your pals are just distractions. I say don't even use the deflect button, just be ready to quickstep behind him as he attacks and get in your sword slashes for good damge, and hopefully your pals help out.
After, go eagle vision to push both buttons on the side of the front wall. Then drop in and enter. This is simple if you want it to be. You can grab, toss him into the wall, kick him while he's down, and grab him to repeat the process until he is down. That or quicksteps for clean punches, but it's the freaking Pope! Fight dirty! Mash the button to finish him.
Then just go on in. There goes the fourth wall...
Follow Lucy and get ready to counter kill everyone.