I'm aware that Ethiopia had an Archbishop who was later sainted, which caused me to think about whether Europe thought of Ethiopia and perhaps Nubia as part of their generalized notion of "Christendom." I'm mostly thinking of the middle ages. Would say an Ethopian Christian traveling Europe during those years be seen as a fellow Christian? Did western European kingdoms view Ethiopia in a similar way they would a place like Byzantium?
Early Middle Ages (5th century AD on wards), Ethiopia enjoyed a good relationship with both Rome and Greece. Christianity wise, Constantius of Rome asked Ezana to send Frumentius (the first patriarch) for questioning but Ezana ignored this request. King Kaleb (also sainted by Eastern Orthodox churches) for instance allied with the Byzantine emperor and aided him in some war.
After Ethiopia was blocked off and made out of reach to most of Europe, there was still small contact with Europe. For instance with Western Europe, i'm aware of envoys sent from Ethiopia to Europe as early as the days of the crusaders. Eastern Europe still made contact as there were already some Armenians and so forth when the Portuguese first came. But the country had little stability at this time due to constant wars, so much so the Kings no longer bothered to build a fortress and lived in tents in their place of residence around the northern central areas always ready to hop off and fight, though they built churches most of which were destroyed by invasion. Any way, wthe contact of this time was very limited and rare and also largely undocumented.
Arround the 16th century, most of western Europe saw Ethiopia as some land of mysteries in which they had some political as well as genuine interest. When they finally did visit, most initially experienced a culture shock. Religion wise, they saw the Ethiopian orthodox Christianity as some sort of hybrid of Christianity and Judaism. They couldn't accept or get why Ethiopians put a great emphasis on the Old Testament laws along side the New Testament and some of the religious practices related to this.
Ethiopians on the other hand, though proud and satisfied with their modest practical lives, admired Europe for its advancement and prestige. Which they once had but still longed for. They also knew that contact was crucial to development and progress but also feared the effect of such interaction on their religion, which to them out weighed all other considerations and later on some additional political suspicion.
Between the 16th to the 18th century, few Ethiopians did voluntarily travel. From what I read about them, they were welcomed kindly and treated really well.