Henry of Sandomierz was the duke of Sandomierz since 1138 or 1146 until his death. He took part in the Second Crusade. Upon his return from the Holy Land, Henry organized a crusade against the Prussians and died in battle.
Rulership
He was the fifth but third surviving son of Bolesław III Wrymouth, Duke of Poland, by his second wife Salomea, daughter of Henry, Count of Berg, from whom he received his name. According to the Testament of his father, Henry inherited the Duchy of Sandomierz, which was at that time in the Seniorate Province of his eldest half-brother and High Duke, Władysław II. Because at the time of Bolesław III's death he was still a minor the Duchy remained in the Seniorate until he reached the proper age, when Władysław had to given him. But Henry could take formal possession of Sandomierz only when the High Duke was deposed and exiled, in 1146. As ruler of Sandomierz, Henry appears only on the occasion of the Act of Foundation of a Church in his land. His ducal title was rarely mentioned by the chronicles, who called him a son of Bolesław IIIWrymouth or brother of Bolesław IV the Curly. Some historians advance a hypothesis that he was the “King of the Poles” mentioned by the Greek chronicler John Kinnamos. If the theory were to be correct, Henry would have been the commander of the Polish contingent in the Second Crusade in 1147. This possible incursion in the Crusades was short, because in 1149, together with his older brother Bolesław IV, he took part in a military expedition in Kiev to support the Grand PrinceIziaslav II.
The first and maybe the most famous of all Sandomierz's dukes, Henry certainly ventured to the Holy Land in 1153-1154 and took part in the Second Crusade under the command of King Baldwin III of Jerusalem. Henry close affiliation to crusading resulted in the establishment of a commandery of the Hospitallers in Zagość. After returning to Poland with an air of holiness, Henry, together with his brothers, organized a crusade against the pagan Prussians. The military expedition, under the command of Bolesław IV and Henry, launched in the second half of 1166. According to the chronicles, Henry was killed in battle against the Prussians. The date of his death, 18 October 1166, was known through indirect sources. However, there is a legend, where Henry apparently was killed in the current Wąbrzeźno County, probably in the vicinity of Nielub or Orłowo, close to the Wieczno Lake.
Succession
Henry never married and hence left no legitimate offspring. In his will, he left his duchy to his youngest brother, Kazimierz II the Just, who until that time, he remained without lands. These last will was done only partially. The destiny of the Duchy of Sandomierz could be shown in a document dated 31 December 1167: The other two parts were taken by the other surviving brothers: Wiślica, was given to Kazimiez II, and the rest to Mieszko III the Old. His remains were probably buried in a crypt of a church in Wiślica, where his grave is marked by an ornamental tombstone donated by his younger brotherKazimierz II. Only in 1173, after the death of Bolesław, Kazimierz finally could take the title of Duke of Sandomierz.