The first Greek millionaire in the Ottoman era was Michael Kantakouzenos Shaytanoglu, who earned 60.000 ducats a year from his control of the fur trade from Russia; he was eventually executed on the Sultan's order. It was the wealth of the extensive Greek merchant class that provided the material basis for the intellectual revival that was the prominent feature of Greek life in the second half of the 18th century and the beginning of the 19th century. Greek merchants endowed libraries and schools; on the eve of the Greek War of Independence the three most important centres of Greek learning, schools-cum-universities, were situated in Chios, Smyrna and Aivali, all three major centres of Greek commerce.