Mieszko I Tanglefoot in 1163, and thanks to the intervention of the Emperor Frederick Barbarossa, Mieszko and his older brother Bolesław I the Tall returned to Silesia. Mieszko and Bolesław I the Tall co-ruled the Duchy of Wrocław during the period 1163–1173. At first, their rule did not extend over the major Silesian cities, which remained under the control of Bolesław IV the Curly, the current High Duke of Poland. The brothers retook them in the year 1165, taking advantage of Bolesław IV's involvement in a crusade against the Prussians. However, soon Mieszko began his efforts to obtain his own Duchy, maybe in
Bolesław the Forgotten calendar was in use so New Year's Day had not been changed to the first day of January. The text describes him as follows: However, there is no mention of any coronation of a Polish ruler in this period, which would have to be recorded in the German sources (as was the case with the coronations of Bolesław I and Mieszko II), probably because there was no royal insignia in the country, which had been returned to the Emperor by the well-known Bezprym earlier in the year 1031. This brief description of Bolesław in the "Wielkopolska Chronicle" is very similar