Shortly after the rich philosophical period of the Greek and Romans, the Abrahamic religions started to emerge. They are known as the People of the Book. Here we see that the old pagan stories, the secular law-making parts, and various elements of Aristotle’s philosophy were weaved into one and ‘modified’ to suit monotheism.
If one unravels the Holy Books than we see that they contain very relevant moral and ethical lessons. At the same time, they continued to include secular law elements aimed at giving the rulers the religious legitimacy to exert their power to enforce their secular rule as well as the adherence to their belief systems.
By the sixth century the Bible started to become taken in a literal sense and it became impossible to philosophise or question beyond that. The Torah had always been taken literally and for the orthodox Jews that is still the case. The Famous School of Athens was closed by the Catholic Church after 1000 years of being the leading institution for learning during Antiquity and Early Modern times.
Over time significant parts of these regions became unmovable dogmas which makes reconciliation between belief systems difficult. This also started to undermine further interrogation into the issues the Greek, Roman and early Christian philosophers were involved in.
Significant philosophers did emerge during the Late Middle Ages such Bede, Grosseteste, Ockham, Aquinas, Abelard, Anselm, Scotus, and others. They were great philosophers however, they were limited to only place their studies and findings within the context of the Catholic faith. It is amazing how close Thomas Aquinas (1225-1274) came to rational truths, science and philosophy would have greatly advanced if he was not hampered by the doctrines of the faith. His theory of just war is still the foundation of the concepts we use today. He also greatly opposed the corruption both in the church and in among the secular rulers. Social justice, unequally, suppression of the poor, fraud and robbery by and from the leaders of his time, were all elements discussed by this medieval philosopher. The most important thing in a government should be that power is subject to the rule of law. While the concept of democracy didn’t exist at that time he eluded to its principles, be it under a benign ruler.. He came close to Hobbes social contract theory that became popular 300 years later.
Similar limitations existed in the Jewish and Muslim faith. If you went beyond that you were very quickly declared a heretic, which meant ousted from society, as there was no separation between the ecclesiastic and the secular world, these simply was no social or economic room in these societies for heretics.
We need to provide special recognition to the Muslim philosophers; they had more freedom and were able to preserve the writings of the Ancients. They occupied the Iberian Peninsula for over 700 years and here in Al-Andalus, the works from the Ancients as well as from the Arabs were translated in Latin.
While there was an early renaissance in the 13th century in Europe, secular philosophy had to stay in exile until the Enlightenment arrived.