In the Fourteenth century, Petrarch claimed that what we now consider the Middle Ages was a period of intellectual decline, which he titled the "Dark Ages." In what he referred to as Europe, he said that classical learning declined greatly. I understand this, while seeing the medieval renaissances as disproving this, but what was the medieval concept of the European continent? As far as I'm concerned, in the Selecluid and Sassanian Empires, classical thought was greatly preserved, and this was transferred to the Abbassid Caliphates. Did the coming of Islam create a divide between what we see as Europe, or did the average medieval person not think of continental borders?
Ooof. That is indeed a question.
The idea of "mental maps" is one that's just coming into vogue in medieval studies, so there isn't a huge amount of literature on this.
If you push me for an answer (which you have), I'd say that my general impression from primary sources is that "Europe" is the territory of the western Roman Empire plus the additions of the Holy Roman Empire. This effectively gives you a map of Christendom in obedience to Rome. You could argue back and forth over the Balkans, but I think the consensus would be mostly not.
The really interesting questions is over Spain - whether or not the Muslim parts were seen as "Europe" and whether or not this changed over time. I have a suspicion that perceptions did indeed change, but I lack the background to demonstrate it. The term "Reconquista" - reconquest - however, would suggest that for the latter Middle Ages, Spain was indeed seen as "Europe".