The Knights Templar is a Christian military order founded in 1119 during the Crusades. Officially known as the 'Poor Fellow-Soldiers of Christ and of the Temple of Solomon,' they were established to protect pilgrims visiting Jerusalem. However, they were disbanded due to the greed of King Philip IV of France.

The Knights Hospitaller originated from an 11th-century medical hospice for pilgrims visiting Jerusalem. Through the Crusades, they evolved into a Christian military order responsible for defending the Holy Land. Their official name is the 'Order of Knights of the Hospital of Saint John of Jerusalem.'

The Equestrian Order of the Holy Sepulchre of Jerusalem was established immediately after the First Crusade in 1099 to guard the tomb of Jesus Christ (the Church of the Holy Sepulchre) and maintain Christian influence in the Holy Land. Today, it survives as a public association of the faithful and a service order under the direct protection of the Holy See.

The Order of Saint Lazarus is a Catholic military order founded in the Kingdom of Jerusalem around the 12th century, with a unique history of focusing on the relief and treatment of leprosy patients. It continues to this day, officially known as the 'Order of Saints Maurice and Lazarus.'

The Sultanate of Rum (1077–1308) was an Islamic Turkic dynasty that branched off from the Great Seljuk Empire. They ruled the Anatolian Peninsula (Asia Minor) in modern-day Turkey and fought against the First Crusade.

The Ayyubid Dynasty was a Sunni Muslim sultanate founded in 1171 by the Kurdish hero Saladin (Salah ad-Din) after he overthrew the Fatimid Caliphate in Egypt. Centered in Egypt, the empire ruled Syria, Yemen, and parts of North Africa during the 12th and 13th centuries, standing as a major opponent to the Crusaders.

The Zengid Dynasty was a Turkic Muslim dynasty that ruled northern Iraq and Syria during the 12th and 13th centuries. They led the Muslim counter-offensive during the Crusades, putting pressure on Crusader states like the Kingdom of Jerusalem, and served as the historical foundation for Saladin's rise.

The Mamluk Sultanate (1250–1517) was a powerful Islamic empire established by Mamluks—soldiers of slave origin—centered in Egypt and Syria. Utilizing the strongest military force of the era, they repelled the Mongol invasions and completely expelled the Crusaders, acting as the protectors of the Islamic world.

The Teutonic Knights were a Christian military order founded at the end of the 12th century during the Third Crusade. While they started in the Holy Land, they have a unique history of later leading the colonization of Eastern Europe and the Christianization of the Baltic coast, establishing a massive monastic state.