It’s dangerous for me to state who is best and worst, particularly since I am not a crusades scholar. I’m using several criteria. There are several aspects that many expected from a good ruler: kindness, generosity to his people, wisdom, and piety (or attention to upholding moral standards of goodness). I’m defining the best men as those who seemed to have these qualities in the greatest number, and I feel justified because these men were renowned as good men in their own time. I’m judging badness by the opposite qualities: cruelty, lack of generosity or love for violence, lack of wisdom or disregard for the advice of those seen to be wise, and disregard for piety from a community who expected leaders to be religious.
The Best: Louis IX and Saladin
I can give no better introduction to Louis IX than Thomas Madden’s: “Much has been written about the character of Louis IX—all of it is good. Even his staunchest enemies agreed that Louis was a man of integrity whose moral character was unassailable and whose devotion to justice was legendary.”  Madden compares Louis IX to Richard I, who was usually depicted as the ideal crusader, but argues that Louis IX was the better king because he was more cautious and deliberative.  Louis IX was not a military authority, but he was a powerful king because of “what the ancient Romans called auctoritas, the authority that one obtains through fame, glory, and moral uprightness.”  Jean de Joinville’s biography shows his love for his people—his generosity towards the poor and the ill, his personal dedication to a simple life, and his great wisdom. (I should stop here or this post will become too long. More on St. Louis when my French is good enough to read more biographies.)
Saladin’s reputation probably needs little explanation, as it has not been tarnished by modern fiction. Saladin was virtually forgotten in the Arab world until around 1899 when colonial schools re-introduced memories of the Crusades to the Middle East,  but that has no effect on Saladin’s deeds. Though he was over-romanticized by Victorian literature, Saladin was widely respected by his opponents in the Crusades, particularly Richard I. He showed great mercy when he was capable of bringing destruction, the taking of Jerusalem being the most prominent of these examples. He treated his opponents with respect and honored the treaties he had entered. Like most leaders, he was capable of great cruelty along with his great goodness, but he was most eager to accomplish his victories through negotiation instead of war.
It is a testament to Louis IX and Saladin that both sides try to claim them. Christian popular myth says that Saladin eventually became a Christian—likewise, popular Muslim myth says that Louis IX eventually became a Muslim. 
The Worst: Frederick II Hohenstaufen and Baybars
I feel justified in calling Frederick II Hohenstaufen the worst of Christian leaders because Madden says “The contrast between the visits of Louis IX and Frederick II could not be more stark.”  Régine Pernoud calls him “The Crusader without Faith.” (However, another good candidate may be Reynald of Chatillon, who was in jail for 16 years because nobody wanted to ransom him.) Upon his coronation, Frederick II had vowed to undertake a crusade, but found excuses to put it off for 13 years. Pope Innocent III excommunicated him for breaking his vow, but Frederick II eventually did go on a crusade when he saw opportunity for personal gain. With a reputation for spectacular failure already building, Frederick II married Isabella in order to become King of Jerusalem, then immediately violated agreements with his father-in-law and seized personal control. Frederick II wanted to fashion himself an absolute ruler in Roman style, in the process alienating many potential allies. He was the only king to crown himself. Piety was an expected priority for Christian kings; since Frederick II showed only contempt for Chrsitianity, most Christian rulers were ashamed of him. Even Muslim leaders felt they would have rather faced anyone else—they could respect many of their opponents, but even when they made treaties with Frederick II, they despised him. 
The word “massacre” frequently and repeatedly appears alongside the name of the Sultan Baybars (also Baibars). Baybars ordered what Madden called the “greatest massacre of the entire crusading era,” the siege of Antioch in 1268, in which he ordered the city doors closed and everyone, including women and children, killed. I feel justified in calling Baybars the worst on his side because Muslim chroniclers were shocked by his orders at Antioch.  This shows me that Baybars’s reputation was a deserved one and not solely the result of exaggeration by his enemies. He made a particular point of enslaving or killing his opponents after promising to spare their lives. While the history of Baybars is far more complex than simply his behavior during the Crusades and I lack the background to even begin writing about his life, it seems safe to say that he is a strong contrast to Saladin.
- I chose this statue of Louis IX because it’s my favorite piece of art depicting him. I chose this statue of Frederick II because it was the only statue on the Wikipedia page. I did not choose these pieces of art for the differences in expression, but it tells you something about the way these two men are remembered.
- Madden, Thomas F, The New Concise History of the Crusades (Lanham, Maryland: Rowman & Littlefield Publishers, 2006), 169.
- Ibid. 169.
- Pernoud, Régine, The Crusaders: The Struggle for the Holy Land (San Francisco: Ignatius Press, 1963), trans. Enid Grant. 319.
- Madden, The New Concise History, 176.
- Pernoud, The Crusaders, 291-92.
- Madden, The New Concise History, 181.