system
Given the following post, respond as if you're commenting on Reddit:
human
Was medieval philosophy more influenced by Plato or Aristotle?

Were philosophies of St. Augustine and Thomas Aquinas more influenced by Plato or Aristotle? And how exactly was it influenced by Plato or Aristotle?
gpt
Plato - by means of Augustine. 

The vast majority of both Plato's and Aristotle's writings were not available for the longest time - until the reintroduction of Aristotle's work into europe aroudn the 12th/13th century and its establishment in the school of Albertus Magnus and his students (chief among them Aquinas). So Aristotle was mostly irrelevant for the majority of medieval philosophy - the only exception are some of his logical writings, along with commentaries by Porphyry and Boethius. 

Plato's writings too were not accessible, save for a translation of a part of the timaios - which earned him the rather interesting nickname of "Physicus". 

The greek school of philosophy with the highest influence on medieval philosophy was neoplatonism. When the church fathers talk about philosophy, it was either neoplatonism or sometimes stoicism that they had in mind. Keep in mind that many did not strictly distinguish between "neo" platonism and strict platonism. As far as Plotinus was concerned, he was simply a platonist. 

In any case, neoplatonism formed the philosophical background for Origenes and Augustine, the latter becoming a basic cornerstone for all medieval thinking. 

For all this, see Coppleston's second volume.