The Spartan misthios Kassandra learned the trade from the likes of Photios and Heitor, and eventually rose through the ranks of the mercenaries to become a legend on her own right, known as the 'Eagle-Bearer' due to the company of her pet eagle Ikaros.
During the Renaissance mercenaries were widespread in Italy, to the extent that guilds devoted to their profession were established throughout major cities such as Venice and Rome. Many among these men were not even Italians, instead hailing from Switzerland, the German states or Hungary. Entire armies could be composed of mercenaries, and their leaders when contracted by Italian city-states or the Papacy were commonly known as condottieri. Such condottieri could garner fearsome reputations, as could be seen in the likes of Federico da Montefeltro, the Duke of Urbino.
By the latter half of the 15th century, Italian mercenaries came to work closely in concert with the Italian Brotherhood of Assassins, who classified them as among three regular factions of allies. This was especially so as the condottieri Bartolomeo d'Alviano, head of the mercenary guild in Venice, was a member of the Brotherhood himself. The Assassins, such as the Florentine Ezio Auditore da Firenze, were accustomed to employing allied mercenaries for street skirmishes or diversions as needed, though their services generally still costed a standard price of 150 florins.
Late in 1499, ahead of Ezio's mission to prevent Pope Alexander VI, the secret Grand Master of the Roman Rite of the Templars, from accessing the Vatican Vault, Bartolomeo transferred his forces to Rome. After Monteriggioni fell to Borgia forces led by Alexander VI's son Cesare Borgia on 2 January 1500, the Italian Assassins, too, relocated their base of operations to Rome for a campaign to unseat Borgia power in the city. In due time, Ezio linked up with Bartolomeo, whose mercenaries were in dire straits of losing their fight against the Borgia. The French Army, with the permission of Alexander VI, had been marching through Italy in an expedition against the Kingdom of Naples, and a detachment under the command of the Templar Octavian de Valois took advantage of this to establish a base in Rome at the Castra Praetoria and assist the Borgia in dislodging the Assassin mercenaries. The arrival of Ezio, however, led to a slow turning of the tide. In August 1503, after Octavian captured Bartolomeo's wife Pantasilea Baglioni in the hopes of forcing Bartolomeo into unconditional surrender, Ezio and Bartolomeo's forces infiltrated the Castra Praetoria disguised as the French in a shocking blow that led to the assassination of Octavian and the withdrawal of his army.
In 1511, a mercenary guild based in the Ottoman Empire's capital of Constantinople was also working in tandem with the Assassins. When Ezio moved to Constantinople under a wider mission to find the keys to the Library of Altaïr Ibn-La'Ahad, he helped to expand mercenary bases in the city, and as before, they proved an asset to the Assassins.
In Rome, the mercenaries acted much as they did in the previous cities, and Bartolomeo d'Alviano and his wife Pantasilea Baglioni led them from their barracks. There, they actively participated in the fight against the Borgia and their French allies, led by Octavian de Valois. When Ezio completed all of the Mercenaries Guild challenges, he was awarded with Bartolomeo's Axe and the guild's crest, which could be located in the armor section in the Tiber Island headquarters.
The services of mercenaries—and often criminals—were regularly employed by both the newly founded Colonial Assassins and their counterparts, the Colonial Templars, in the British colonies of continental America. In 1754, several mercenaries hired by the Assassins captured the research notes of Templar William Johnson that detailed the region inhabited by the Kanien'kehá:ka. They guarded these in an encampment in west Boston while the Templar soldier Thomas Hickey was tasked by Johnson to perform reconnaissance on the compound. Not long after, the Colonial Rite's new Grand Master, Haytham Kenway, had arrived from England, and he, his protegé Charles Lee, and Hickey infiltrated the fort and retrieved the notes.
In general, the line between mercenaries, official members, and criminals blurred for the Colonial branches of Assassins and Templars. Hickey was a particular example, for though he was treated as a core member of the Colonial Rite, working closely with its leaders Haytham, Charles, and Johnson, his only motivation was profit, caring not at all for the Templars' goals. Meanwhile, the Assassin Hope Jensen took control of the gangs throughout the colonies of northeast America and carved out a wide criminal network whose brigands served as her forces for the Assassins. These gangs were, in a sense, functionally mercenaries operating out of numerous bureaus and cells in New York and in the wilderness of Halifax and the Hudson River valley. However, during the French and Indian War, the Templar Shay Cormac and the British Army managed to break their power and scatter them, killing Jensen herself in 1759.
By the end of the conflict, the Colonial Brotherhood had been all but destroyed, with only its Mentor Achilles Davenport surviving as a cripple. Thus in the following decades, mercenaries ceased to be an asset of the defunct Colonial Brotherhood, whereas they persisted as a significant part of the Colonial Rite's forces into the American Revolution. The British hired an army of German mercenaries called Hessians, among their fiercest officers were the Jägers, which Ratonhnhaké:ton faced on more than one occasion. On 4 July 1776, Hickey was assassinated by the Assassin Ratonhnhaké:ton, the son of Haytham better known as Connor, moments after the Mohawk Assassin was saved from public execution with the help of Achilles and the reformed Colonial Brotherhood. A significant number sided with Benjamin Church following his desertion of the Templar Order, working to protect him from the retribution of Haytham, a task they would ultimately fail in 1778 when Benjamin was killed by the combined efforts of Haytham and Ratonhnhaké:ton on his ship, the Welcome, off the coast of Martinique.