Armor

Designed to provide protection to the wearer, armor was composed of metal plating or leather pieces, and was available for purchase at blacksmiths. As a benefit, armor fortified the health and damage resistance of the wearer, however, armor could also be broken if it took too much damage, causing a temporary loss in the wearer's maximum health until it was repaired.

High Middle Ages
During the Crusades, Altaïr wore a standard Assassin combat uniform that primarily consisted of vambraces, greaves, shoes and a protective belt, all made in leather. The main vambrace, which was always worn on an Assassin's left forearm, concealed the Hidden Blade with a series of metal plating arranged in formation for combat protection.

As an Assassin was promoted through the ranks of the Order, his waist belt would also be upgraded to reflect the new-found status. Altaïr and Malik Al-Sayf both bore the highest level of combat uniform in the Assassin's Order, with the most prestigious three-layer waist belts.

Codex
Using the Apple of Eden, Altaïr created the Codex pages, as well as a new suit of armor for himself, one that was almost impossible to damage. This new armor would be passed down to each of his descendants, eventually being hidden away in the Sanctuary beneath the Villa Auditore.

Other
Armor did appear on other individuals, and there was differences in the styles worn by guards in each city.

The guards in Damascus could be found in either lamellar, leather, or ringmail armor. Guards in Acre could be seen in brigantine armor and chain mail, some complete with coifs, while guards in Jerusalem were often found wearing scale or splintmail. Each of these guard types could be found in the Kingdom, near to their respective cities.

The Knights Templar uniformly wore full suits of chainmail, covered in a white tabard with a red steel helm covering their face. Accompanying this, they wore their signature red cross openly, possibly due to their public image, whereas future Templars wore the symbol more subtly, as the Templar Order faded into obscurity.

Italy
Ezio Auditore could purchase different types of armor from blacksmiths found throughout the various cities of Italy, with there being four sets of armor to purchase, and a fifth – the Armor of Altaïr – which could be gained through acquiring all of the Assassin's seals. Each set contained four individual pieces: chest plates, greaves, spaulders, pauldrons, and vambraces.

Statistics
Leather Armor was the first available armor which fortified health, but offered no resistance bonuses. Later, Ezio could purchase Helmschmied armor, which was a variant of leather with metal inlays. Some time after, Ezio could also buy Metal and Missaglias armor, both composed mainly of metal, with Missaglias sporting stylized decoration.

Every armor after the leather set offered both health fortification and resistance bonuses, but considering that armor could be damaged through combat or by falling from large heights, it was necessary to repair it at blacksmiths regularly.

Each armor was represented with set number of circles, displaying the level that it could resist becoming damaged. In general, when twenty squares of damage was inflicted to the synchronization bar, it would remove one circle of resistance from every piece of armor one had equipped.

Armor of Altaïr
After collecting the seals from the tombs of six historic Assassins, Ezio could unlock Altaïr's improved armor from behind a gate in the Sanctuary. It consisted of black cloth with specially made armor integrated into it, akin to the mythical properties of the Golden Fleece.

As such, the armor never required any repairs to be made to it. In page 19 of Altaïr's Codex, it revealed that the armor was the only suit made by Altaïr, who destroyed the written formula out of fear of the armor becoming widely used by either friend or foe alike.

Others
All types of soldiers in Italy were armored to varying degrees, with archers as the lightest units, followed by Agiles, regular soldiers, Seekers, and Brutes. Elite soldiers wore heavier armor than regular soldiers, making them more resistant to Ezio's attacks and counter-attacks.

Rome
During the siege of Monteriggioni, Ezio lost the Armor of Altaïr underneath the rubble caused by a cannonball striking the Villa, forcing him to run into battle clothed in a simple shirt, trousers and boots. Later on in Rome, Ezio's new robes and armor were anonymously given to him by Machiavelli, through the woman that nursed his wounds from the bullets fired by arquebusiers during the siege.

Ezio's newer attire resembled the clothes of Altaïr, with longer robes and a longer hood, while his new armor came only with a spaulder and a single vambrace.

Just like in previously visited cities, Ezio was able to purchase armor upgrades from a blacksmith shop, though it was also possible for him to complete specific quests for the blacksmith shop on Tiber Island, in order to unlock parts of the Seusenhofer armor.

The only set that could not be purchased was the Helmschmied Drachen Armor, though it was available as an outfit with the purchase of The Da Vinci Disappearance DLC.

Statistics
In Rome, armor designs had changed to the degree that they were given metal inlays during the second and last set of purchasable armors. The Roman armor set was made of leather, while the Rondelle armor set had the same design with metal inlays.

Also, the Plate armor was the unstylized version of the Seusenhofer armor with metal inlays, whereas the Seusenhofer was more decorated than its predecessor.

Later, when Ezio had obtained all six of the Keys of Romulus, he was given access to the Armor of Brutus, which was an unbreakable armor contained behind a gate underneath some ruins in the city.

Others
Guards were armored similarly those stationed in other Italian regions, with the addition of the Papal Guard as the most heavily armored opponents. Of the new guard archetypes, the Crossbowmen were equal in defense to Archers, while Arquebusiers matched standard guards.

Constantinople
During Ezio's travels in Constantinople, he encountered a new variety of armor. From blacksmiths, he could acquire Azap leather armor, which was the weakest, followed by Mamluk metal armor and the Sepahi Riding armor in terms of strength.

Additionally, upon initiating the advanced training of seven Assassins into becoming Master Assassins, through the first part of their specialised mission, Ezio acquired the Master Assassin armor.

Also, after spending some time in the city and finding all ten of Ishak Pasha's memoir pages, he then journeyed inside the Hagia Sophia and completed a harsh climb to a secret room within the mosque, in order to obtain the Armor of Ishak Pasha from the Assassin's tomb.

Recruits
Ezio's Assassin Apprentices in Rome and Constantinople could also wear armor, which was upgradeable as the Apprentice progressed along the ranks of the Brotherhood.

At first, a recruit started with no armor, but could acquire leather pauldrons, leather greaves, a leather chest guard, and finally a full set of plate armor, which would replace their previous leather pieces.

Once they had obtained the plate armor, the recruits would be able to last very long in battle, and were less likely to get killed. On reaching the rank of Assassin however, they would gain new robes resembling that of Ezio's Master robes in Rome, with Assassin armor even stronger than plate armor. In Constantinople, the recruits would gain robes similar to that of Yusuf Tazim, along with the armor of a fully-fledged Assassin.

Trivia

 * Assassin's Creed II was the only game where armor took on a damaged appearance when broken.
 * In Assassin's Creed II, the Missaglias Vambraces had 1 more health square than the Vambraces of Altaïr.
 * Ezio's initial spaulder in Rome was made out of leather, while the cover art of Brotherhood depicted him wearing a metal spaulder. His initial Hidden Blade bracer was the same as it was on the cover, however, like the metal spaulder, Ezio's second Hidden Blade appeared differently. Instead, it was a brown glove like his original second Hidden Blade used in the Assassin's Creed II E3 demo, and also on pre-released Assassin's Creed II pictures. Meanwhile, on the cover art for Brotherhood, the second blade was originally displayed as an identical blade and bracer to that of his primary Hidden Blade.
 * The Armor of Altaïr's greaves had patterns similar to that of the Helmschmied Chest Guard and the Helmschmied Spaulders.
 * Vambraces for the second Hidden Blade could only be bought at a blacksmith once the Hidden Blade itself was purchased from Leonardo da Vinci.
 * The Armor of Altaïr and the Armor of Brutus both gave 25 health squares without the need of repairs. However, in Revelations, the Armor of Ishak Pasha and Master Assassin Armor only had a maximum of 20 health bars, though they were still unbreakable.
 * There was a glitch in the second sequence of Brotherhood, where if Ezio visited a blacksmith before the memory "New Man In Town", the entire Seusenhofer armor set would be available for sale, although only the greaves were able to be bought since the gauntlets required the dual Hidden Blades, and the pauldrons and chest guard were unlocked through a shop quest.
 * With the Master Assassin armor equipped, Ezio's clothing color was returned to the default, "Original Grey", though it would stay that way until he unequipped the Master Assassin armor. It would still be possible to dye his clothes, however, this would not be noticeable until he had removed the armor. Additionally, like the Armor of Ishak Pasha, the hood would remain on in cutscenes.
 * Ezio's Master Assassin Armor in Constantinople had the hidden effect of not causing any footstep noise while running, which gave "complete stealth" as described in the game.
 * The Armor of Ishak Pasha had the hidden effect of extra projectile resistance and had a small chance to deflect the projectile back at the shooter.