Final answer:
The Christians did not lose the Crusades because they had the strongest army in the world; they lost in part due to disorganization, poor leadership, lack of training, and disease. The decline in the power of the popes and post-Black Death shifts in feudal society also contributed to the decline in crusading in the Middle Ages.
Step-by-step explanation:
The reason the Christians lost the Crusades was not because they had the strongest army in the world. In fact, during the Crusades, the Christian armies faced numerous challenges such as disorganization, poor leadership, lack of training, and the ravages of disease. Their armies were often composed of various social classes, including commoners, women, and even the sick, which could affect their military discipline and effectiveness. Furthermore, the logistical issues of moving large numbers of people across Europe and the complex international politics of the time also contributed to their difficulties. Disease was particularly debilitating during the later crusades and significantly reduced the fighting capacity of Christian armies.
One of the reasons for the decline in crusading in the later Middle Ages included the decline of the power and influence of the popes, who were the spiritual leaders advocating for these religious wars. After the Black Death, a decline in feudalism also occurred as many peasants moved away from rural areas in search of better opportunities, which in turn could have negatively impacted the recruitment and support base for the crusades.