A flag is a piece of fabric, often decorated with a distinctive design or emblem, used as a visual symbol or signal. It may also refer instead to an exact reproduction or illustration of such an object on a medium.
Throughout history, flags have been used by states and factions to represent themselves and signify their presence. Flags are carried alongside armies so that their affiliation may be identified or planted in high places, such as atop towers and walls, to declare that territory under the political control of the faction the flag represents. Accordingly, flags can also serve as powerful rallying devices, inspiring public and military morale in the face of conflict or adversity. Because of this, it was an occasional practice of the Assassin Brotherhood to remove flags of their enemies, particularly the Templars, across cities in which they wish to wrestle influence.
Flags were scattered by members of various factions throughout the Holy Land to lay claim to particular regions of territory. There were different kinds of flags, each representing a different faction. Present in each district visited by Altaïr during his hunt for the Nine, they represented the key military powers in the region. 
|Image||Flag name||Location||Number of flags|
|King Richard flags||Kingdom||100|
The Borgia also used flags to increase their control over Italy. There were 101 Borgia flags to collect in Rome. However, art merchants in the city sold maps which made it easier for Ezio Auditore da Firenze to find and remove all of the Borgia flags. An additional method to locate the flags was through Ezio's use of Eagle Vision, thus marking the flag on the map. Collecting all 101 flags rewarded Ezio with the Borgia cape. Additionally, during the Venetian games of Carnevale, the "Capture the Flag" event used a flag that Ezio had to retrieve and return to his starting point to score.
Golden Age of Piracy
During the Golden Age of Piracy, nearly all ships had a flag on the top of their mast to show an allegiance to their countries. During a boarding of an enemy vessel, Edward Kenway and Adéwalé would sometimes cut down the ship's flag upon claiming it. In 1719, Kenway was tasked with stealing a Portuguese flag, in order to disguise his ship as one of their own.
During the American Revolutionary War, after Connor killed a British Army captain and destroyed the powder reserves in one of the many forts in Boston, New York, or the Frontier, he would then take down the British flag and replace it with an American one, liberating the fort and claiming it for the Patriots.
- In Assassin's Creed, Altaïr sometimes had to prove himself to informants by collecting several Assassin flags in a certain amount of time. Upon finishing the task, Altaïr would receive information about his target.
- The Capture the Flag achievement could be earned by collecting the 101 Borgia Flags scattered around Rome.
- When taking over an Assassin-affiliated gang headquarters, the Templar Shay Cormac would cut down the gang's flag, and subsequently burn it.