in Vita Sancti Adalberti Pragensis by various authors, the earliest being traced to imperial Aachen and the Bishop of Liège, Notger von Lüttich, although it was previously assumed that the Roman monk John Canaparius wrote the first Vita in 999. Another famous biographer of Adalbert was Bruno of Querfurt who wrote a hagiography of him in 1001–4. Notably, the Přemyslid rulers of Bohemia initially refused to ransom Adalbert's body from the Prussians who murdered him, and therefore it was purchased by Poles. This fact may be explained by Adalbert's belonging to the Slavniks family which was rival to the Přemyslids. Thus Adalbert's bones were preserved in Gniezno, which assisted Boleslaus I of Poland in increasing Polish political and diplomatic power in Europe. According to Bohemian accounts, in 1039 the Bohemian Duke Bretislav I looted the bones of Adalbert from Gniezno in a raid and translated them to Prague. According to Polish accounts, however, he stole the wrong relics, namely those of Gaudentius, while the Poles concealed Adalbert's relics which remain in Gniezno. In 1127 his severed head, which was not in the original purchase according to Roczniki Polskie, was discovered and translated to Gniezno. In 1928, one of the arms of Adalbert, which Bolesław I had given to Holy Roman Emperor Otto III in 1000, was added to the bones preserved in Gniezno. Therefore, today Adalbert has two elaborate shrines in the Prague Cathedral and Royal Cathedral of Gniezno, each of which claims to possess his relics, but which of these bones are his authentic relics is unknown. For example, pursuant to both claims two skulls are attributed to Adalbert. The one in Gniezno was stolen in 1923. The massive bronze doors of Gniezno Cathedral, dating from around 1175, are decorated with eighteen reliefs of scenes from Adalbert's life. They are the only Romanesque ecclesiastical doors in Europe depicting a cycle illustrating the life of a saint, and therefore are a precious relic documenting Adalbert's martyrdom. We can read that door literally and theologically. The one thousandth anniversary of Adalbert's martyrdom was on 23 April 1997. It was commemorated in Poland, the Czech Republic, Germany, Russia, and other nations. Representatives of Catholic, Eastern Orthodox, and Evangelical churches traveled on a pilgrimage to Adalbert's tomb located in Gniezno. Pope John Paul II visited the cathedral and celebrated a liturgy there in which heads of seven European nations and approximately one million