When it comes to fierce fighting, it's tough to top The Knights Templar. The order was criticized throughout history for many of its mediocre characteristics. Yet, they were always praised for their bravery and courage.
In the twelfth century, while Christian travelers were often attacked on their trading trips, a small group appeared in the Middle East and named themselves The Poor Knights of the Temple of King Solomon, later shortened to the Knights Templar. At first, the order aimed to protect and defend travels and the new converts. Later, it became a well-recognized political and military force in the East and Europe.
The Templars introduced a new model of religious fighting to history. King Arthur's legend and his knights' search of the Holy Grail wouldn't make any sense if it weren't for the Knights Templar.
Before the order, knights were considered thugs that roam the country, looking to fill their pockets. The Knights of the Templar, on the other hand, were monks who swore to chastity and fought for higher causes rather than money.
Also, the Templar's discipline was exemplary. They lived by the Rule, which organized all different aspects of their lives and had regulations when it comes to wars. The Knights were not to surrender under any circumstances. Unlike many Christian forces in the Middle Ages, they were well trained and fought fearlessly. In the Battle of Montgisard of the Crusades, they were able to defeat, next to an outnumbered Christian force, Saladin's great Muslim army.
Perhaps the Templars were different from the other knights because their courage came from a devotion to the Christian values where breaking a sacred vow is worse than dying in battle. However, their discipline was also a result of their obedience to the Templar Rule that calls never to surrender unless ordered to so.