Complex sentence: Albero de Montreuil (c.1080--18 January 1152) was Archbishop of Trier from 1131 to 1152 and is the subject of the "Gesta Alberonis".
Split into simpler sentences: Albero de Montreuil (c.1080--18 January 1152) was Archbishop of Trier from 1131 to 1152. He is the subject of the "Gesta Alberonis".