Stronsay or Sdronsay, so called as if ‘Streams Isle.’ This island is six miles in length and four in breadth: peats are abundant here, and half part is uncultivated. Some here worship God, others not. They also greatly believe in fairies, and say men dying suddenly afterwards live with them, although I do not believe it. Troici, under the name of a marine monster, very often cohabit with women living here, which, when I lived there, a beautiful woman was there married to a sturdy farmer; she was tormented with a great spirit, and was seen against the husband’s will lying in one bed, and he cohabiting naturally with the women. The woman at length became emaciated from sorrow: I advised that she might get free by prayer, alms-giving, and fasting, and which she did; she was thus troubled during a year. The description of this monster is this. He was covered with marine plants over the whole body, he was similar to a young horse covered with hair, he had a member similar to a horse and large testicles.
A Description of the Orkney Islands by Jo. Ben, 1529