Question: The papal election of 1159 followed the death of which pope, who ruled from 1154 until 1159?

Related documents: [0]  [DOC] The Papal election of 4–7 September 1159 followed the death of Pope Adrian IV. It resulted in a double election. A majority of the cardinals elected Cardinal Rolando of Siena as Pope Alexander III, but a minority refused to recognize him and elected their own candidate Ottaviano de Monticelli, who took the name Victor IV, creating a schism which lasted until 1178. [END] 
[1]  [DOC] Pope Adrian IV (Latin: "Adrianus IV" ; born Nicholas Breakspear;  1100 1 September 1159) was Pope from 4 December 1154 to his death in 1159. [END]  
Answer: Pope Adrian IV
Pope Adrian IV