Assassin's Creed II Guide - Walkthrough
Sequence 3: Requiescat in Pace
Memory 1: Roadside Assistance
Start down the trail and you will soon be stopped by the Pazzi. Vieri de' Pazzi will send two men after you. Equip the Hidden Blade if it isn't already by pressing up on the D-pad and immediately walk up to one of the enemies and press the X/Square button to ice him. The second enemy will likely go for Claudia and Maria; walk up behind him and use the Hidden Blade to kill him.
Defend Claudia and Maria from the Pazzi.
When the two goons are dead, a cutscene will ensue. Ezio's uncle Mario appears with his men, throwing Ezio a sword. When you regain control over Ezio, select the Long Sword by pressing right on the D-pad. Mario brought some allies with him, so with any luck most of the enemies will be preoccupied fighting them.
Walk up behind enemies who are busy fighting and hit the X/Square button to effortlessly kill them. If an enemy happens to turn to you, hit the X/Square button repeatedly to deplete his health, or perform a Counter Kill by holding RT/R2 and pressing the X/Square button just as his strike is about to connect
Help Mario and his men kill all of Vieri's goons to complete the memory.
Memory 2: Casa Dolce Casa
Enter Monteriggioni and speak to Mario to begin this memory. Follow Mario up to Villa Auditore at the north end of Monteriggioni. After a short chat, Mario will give you some florins. You must visit the Blacksmith in Monteriggioni and purchase a Dagger and Greaves. Follow the green marker on the Mini-Map to reach the Blacksmith. Buy the Leather Greaves under the Armor category for 1140 florins, and the Dagger under the Small Weapons category for 475 florins. Equip the Dagger by holding RB/R1 and selecting it with the Left Stick.
Purchase Leather Greaves and a Dagger from the Blacksmith in Monteriggioni.
Once you have the Greaves and Dagger, visit the Doctor a few steps from the Blacksmith and fill your Medicine Pouch with five Medicine. To speed the process up, press the X/Square button after selecting the Medicine and then the A/X button to purchase the maximum amount. Press the left D-pad button to use the Medicine and complete the memory.
Memory 3: Practice Makes Perfect
Enter Villa Auditore, speak to Claudia and then to Mario to get started. You're going to practice a few basic combat skills in the practice field in front of the villa. Follow the instructions onscreen to complete the Quickstep, Counter Kill, and Taunt training. You then must defeat Mario, which is ridiculously easy.
After defeating Mario, follow the marker on the Mini-Map to the Codex Wall room in the Villa to complete the memory.
Memory 4: What Goes Around
Head upstairs to Maria's room to speak to Claudia. Collected Feathers can be delivered to the Feather chest in Maria's room. Deliver 50 Feathers to unlock the Condottiero War Hammer, and all 100 to unlock the Auditore Cape.
After seeing Maria, get on the horse at the stables outside of Monteriggioni and follow the marker on the Mini-Map to travel to Tuscany. Meet Mario and his men at the marker outside of San Gimignano to begin the memory.
Activate the lever to raise the portcullis.
Run up the hill with Mario to the south wall of San Gimignano. At the wall, Free-Run up the stack of crates to climb up. Equip the Throwing Knives you've been given by holding RB/R1 and selecting them from the weapon wheel with the Left Stick. While standing in the marker on the wall, lock on to the archer on the rooftop across the street and hit the X/Square button to throw a knife his way. It only takes one throwing knife to kill these guys.
There are three more archers by the gate; two of them are on rooftops, and the other is in the tower above the portcullis. Make your way over to these archers and use Throwing Knives to kill them. After killing the archer in the tower, drop done to the turnwheel next to the gate and press the B/Circle button to interact with it
Storm San Gimignano in search of Vieri de' Pazzi.
When the gate is open, help Mario and his men finish off the guards outside the walls, and then follow them as they enter the city. Mario will give you command over a few of his men, who you can use to occupy the nearby guards. Lock on to one of the guards and press the Y/Triangle button to command the Mercenaries to attack. Help the Mercenaries kill 10 of the guards and then start toward the green marker on the Mini-Map. Speak to the wounded mercenary by the well and then head up the steps to aid Mario.
Equip your Long Sword if it isn't already (press right on the D-pad). Target preoccupied guards and effortlessly kill them by pressing the X/Square button from behind. Continue killing guards until another green marker appears on the Mini-Map, at which point start heading toward it. Hit the marker on the roof to trigger a cutscene.
Entering San Gimignano
After the cutscene, Vieri will appear on the tower next to the gate. Climb up the scaffolding west of the gate and walk along the wall to the tower. Jump and grab hold of the one of the protruding stones along the side of the tower and climb up to the ledge. Vieri will automatically detect you when you pull yourself up, so be ready with your Long Sword or Hidden Blade to Counter Kill him.
Assassinating Vieri de' Pazzi
Memory 5: A Change of Plans
Speak to Mario outside of Villa Auditore to get started. Follow him into the villa, into the Codex Wall room, and speak to him again there. There are four philosophical Codex pages in Monteriggioni -- you must collect all four to complete this memory.
Synchronizing the Viewpoint on top of the villa will mark the location of all four Codex pages on the in-game map. Head over to the northwest side of the building, climb up to the roof and then up onto the Viewpoint. Synchronize the Viewpoint before performing a Leap of Faith.
Synchronize the Villa Auditore Viewpoint to reveal the locations of the four philosophical Codex pages in Monteriggioni.
Three of the Codex pages are within the commune walls, and the last is by the house at the east end of the map. Make your way to each container and hold the B/Circle button to retrieve the Codex page inside. Collect all four Codex pages to complete the memory and Sequence 3.