The medieval period in European history covers over a thousand years of development, from the fall of the Roman Empire in the 5th century to the beginning of the Renaissance in the 16th century. Nearly all of the medieval thinkers – Jewish, Christian, and Muslim – were pre-occupied with the attempt to synthesize philosophy with religion. Early on, the Neoplatonism of Plotinus provided the most convenient intellectual support for religious doctrine. Later in the medieval era, thanks to the work of the Arabic-language thinkers, the ancient Greek texts from Plato and Aristotle were re-introduced to Europe and translated directly into Latin. The synthesis between ancient Greek thinking and Christian theology deepened and culminated in the philosophical theology of Thomas Aquinas, which became a foundation for Catholic theology until today. The goal was to provide a philosophical foundation for theological positions. In the process, much of that foundation was effectively absorbed into theology itself, so that much of what we now consider Christian doctrine has its origins in Greek philosophy.
Good summaries of Medieval Philosophy can be found here:
- Spade, Paul Vincent, “Medieval Philosophy”, The Stanford Encyclopedia of Philosophy (Spring 2017 Edition), Edward N. Zalta (ed.), URL = <https://plato.stanford.edu/archives/spr2017/entries/medieval-philosophy/>.
- Wikipedia: Medieval Philosophy.