Before the 1600s, where did europeans gather their knowledge from?

In the 11th century Europeans and Islamic people began to fight for Jerusalem. Jerusalem was important to the Europeans because it's where Jesus was sacrificed and Jerusalem was important to the Islamic people because The Dome Of Rock (a shrine) resided there. Before the Crusades the European people were very isolated and lived in a feudalist society on Manors. This was considered the medieval times in Europe. After Europeans went to was they finally experienced the outside world and slowly discovered the history of Greeks and Romans. In the 1300s the renaissance (the word means reborn) began due to the fact that the Europeans medieval ways was much worse than living like a Greek or a Roman. The renaissance is where Europeans gained their knowledge. The Europeans learned culture, art, literacy and among many other things that helped them dive into modernity.