Complex sentence: He was elected King of Germany at Frankfurt on 4 March 1152 and crowned in Aachen on 9 March as King of Italy in Pavia in 1155, and finally crowned Roman Emperor by Pope Adrian IV, on 18 June 1155.
Split into simpler sentences: He was elected King of Germany at Frankfurt on 4 March 1152 and crowned in Aachen on 9 March 1152. He became King of Italy in 1155 and was finally crowned Roman Emperor by Pope Adrian IV, on 18 June 1155.