tired after a busy hunting day, Gediminas had a prophetic dream about an iron wolf howling on a top of the hill. When he asked a krivis (a pagan priest) Lizdeika for an explanation of the dream, he was told that he must build a castle on the top of that hill, which is strategically surrounded by three rivers (Neris, Vilnia, and Vingria (now underground)) and a grand city around that hill, so that "the iron-wolf-like sound about this great city would spread around the world". Some versions of this tale state, that for his advice, Lizdeika was given a name of Radziwiłł. The derivative of the Lithuanian name Radvila has also been interpreted as derived from Belarusian радзіць or Polish radzi 'advises'. The Lithuanian word for 'wolf' is vilkas. English king Henry IV spent the full year of 1390 supporting the unsuccessful siege of Vilnius by Teutonic Knights with his 300 fellow knights. During this campaign, Henry Bolingbroke also bought captured Lithuanian princes and then apparently took them back to England. King Henry's second expedition to Lithuania in 1392 illustrates the financial benefits to the Order of these guest crusaders. His small army consisted of over 100 men, including longbow archers and six minstrels, at a total cost to the Lancastrian purse of £4,360. Much of this sum benefited the local economy through the purchase of silverware and the hiring of boats and equipment. Despite the efforts of Bolingbroke and his English crusaders, two years of attacks on Vilnius proved fruitless. Between 1503 and 1522, for the sake of protection from Crimean Tatar attacks, the city was surrounded by defensive walls that had nine gates and three towers. Communities of Lithuanians, Jews, Ruthenians, and Germans were present in different areas of Vilnius. The Orthodox inhabitants concentrated in the eastern part of the city left of the "Castle Street", while most Germans and Jews occupied the western side of the city around the "German Street". The town reached the peak of its development under the reign of Sigismund II Augustus, Grand Duke of Lithuania and King of Poland, who relocated there in 1544. In the 16th century, Vilnius became a constantly growing and developing city, as Grand Duke of Lithuania and King of Poland Sigismund II Augustus and his mother queen Bona Sforza were spending much of their time in the Royal Palace of Lithuania. The Polonization of Vilnius proceeded