What are the reasons for the weakening of absolute Ijtihad between the seventh and thirteenth centuries AH?

Among the reasons for the stagnation of ijtihad (definition) (independent reasoning) were the codification and stabilization of the followed madhahib (schools of thought) and people's trust in them, as well as their adoption by some politicians. This was in addition to fanaticism for the madhahib and some of their proponents asserting that the door of ijtihad was closed, thereby restricting mujtahids (those who practice ijtihad). This stagnation was not limited to the religious sphere but also reflected on other aspects of life. Some historians believe that intellectual stagnation and jurisprudential تقليد (taqlid (definition), imitation) began from the middle of the fourth century Hijri until the end of the thirteenth century. Nevertheless, in every era, there were imams, scholars, and mujtahids, confirming the words of the Messenger of Allah, peace and blessings be upon him: "This knowledge will be carried by the trustworthy of every generation, who will repel from it the alterations of the extremists, the imitations of the falsifiers, and the interpretations of the ignorant."