Of greater importance was Iaroslaf's work at home. He built (p. 045) churches and monasteries; St. Sophia church was the pride of Kief; the monastery of The Catacombs still draws pilgrims from all parts of Russia. Kief became known as "the city of four hundred churches." He also founded a school for three hundred boys at Novgorod, thereby showing that Russia at that time was second to no European nation. Kief, under his reign, was one of the most prosperous cities. This was due to her situation on the Dnieper and her trade with the Byzantine Empire, to the great fertility of the Black Earth land, and to Iaroslaf's connection by marriage with the reigning families of Europe. Of his daughters Elizabeth was the wife of the King of Norway, Anne of the King of France, and Anastasia of the King of Hungary; his sister Mary was married to the King of Poland, and his sons had married into royal families. Merchants from Holland, Germany, Hungary, and Scandinavia were established at Kief. The Dnieper was alive with merchant vessels, and she counted eight markets. It is evident that Iaroslaf took pains to protect and advance commerce. He had coins minted with his Slav name on one side, and his Christian name Ioury (George), on the other. Perhaps his greatest work is the code of laws established by him, known as the _Russkaia Pravda_ or Russian Right. Though necessarily primitive, it was a long step in advance of that time. It followed chiefly the ideas of right and wrong according to the conceptions of the Scandinavians. At this time, although the dignity of _kniaz_, duke or prince, was (p. 046) hereditary in the family of Rurik, it was understood by all parties that the reign of the prince depended upon the consent of his subjects, and perhaps more still upon that of his drujina. A story is told that in Vladimir's time the drujina complained that they were made to eat from wooden bowls, whereupon he gave them silver ones, saying: I could not buy myself a drujina with gold and silver; but with a drujina, I can acquire gold and silver, as did my father and my grandfather. Ever since Kief had been the residence of Rurik's descendants, they had been recognized as Grand Dukes, because they represented the eldest of the descendants. They did not, as a rule, interfere with the administration, but were the dukes, the commanders of the armies. Many districts had such a duke, who was, however, invariably of the blood of Rurik, and recognized the superior authority as the eldest of the blood. When the Grand Duke of Kief died, he was not succeeded by his son, unless he had neither uncle nor brother living; but it was within the power of the grand duke to leave one or more districts to his sons.