Felix Fabri (1438-1502, born in Zurich), was a Dominican theologian who wrote several books about his travels in the Holy Land.
"In Egypt, just before his final departure for home, he met a holy man. The boat from Cairo to Alexandria was joined by a Muslim ascetic from an order vowed to perpetual silence: here was a man, Fabri wrote, 'of so great, and if it is not wrong to say it, of so spiritual a discipline as could nowhere be found among the Religious [Orders] of Christendom, and it was as if the holiness of the man shone in his countenance. I would have been glad to speak with him if I had known his language.' It is a sudden, blessed moment of genuine respect. A barrier dropped.”
Peter Brown, "Jerusalem, 1000-1400: Every People under Heaven," New York Review of Books, 8 December 2016.