Princely brothers and sisters : the sibling bond in German politics 1100 1250 The origins of twelfth century princely lineages Forging the bonds between siblings : succession inheritance and church careers Baby boomers : the first generation of the Staufen upper aristocracy Frederick Barbarossa and Henry the Lion : cousins in an age of brothers Cooperation conflict and the rise of a new generation ca. 1180 1210 From Bamberg to Budapest : four brothers and four sisters in the early 13th century The uncertain future of lineages : siblings during the reign of Frederick II