Abul Qasim Ubaidullah ibn Abdullah ibn Khurdad-bih a.k.a Istakhri was a midieval Persian prominent geographer.
Among his works we find Al-masalik wa al-mamalik and his al-Aqalim.
It was Istakhri who first gave the earliest known account of windmills. Pitstone Windmill, believed to be the oldest windmill in the British Isles A windmill is an engine powered by the energy of wind. ...
Istakhri in his Masalik wa Mamalik states that pearls were in existence on the coast of the Persian Gulf and goes on to state, "and with the exception of the Persian Gulf, there are no other places that have pearls."
It was first mentioned in about 850 CE as a flourishing port, and Istakhri states that in the tenth century it was a prosperous city rivaled only by Sheraz in the province of Persis.
Istakhri states that the houses in Sirāf were built with a wood called Saj, brought from India and Zanzibar,