Marek Smoliński. Joannici w polityce książąt polskich i pomorskich. Od połowy XII do pierwszego ćwierćwiecza XIV wieku [The Hospitallers and Their Involvement in the Politics of Rulers of Poland and Pomerania. 1150–1315]. Gdańsk: Wydawnictwo Uniwersytetu Gdańskiego, 2009. Pp. 379. ISBN 978 83 7326 519 6.

The spread and influence of crusading ideology in Bohemia and Poland

“…This expansion points to the personal reasons behind Henry's donation, possibly influenced by his brother's political connections. Regarding the Czech influence in this process, Silesia emerged as a crucial region in Poland with a high concentration of foundations for the Knights Hospitaller 46 . These establishments likely predated those in Zagość and may have been influenced by Czech and Moravian dynasts under Frederick I Barbarossa's influence, including figures like Vladislav II, Sobiesław II, Fridrich Bedřich, and Conrad III Otto.…”