In Berlin between 30 May/6 June 1423 , William married firstly Cecilia ( c. 1405 – 1449 ) , daughter of the Hohenzollern elector Frederick I of Brandenburg .
Head entity: cecilia Q299925 11
Tail entity: frederick i of brandenburg Q61336 24 25 26 27
Relation (head \u2192 tail): P22
Inverse relation (tail \u2192 head): P40