upright=1.35|thumb|Emperor Frederick I (middle) flanked by his two sons, Henry VI and Frederick VI. Year 1155 (MCLV) was a common year starting on Saturday of the Julian calendar.
upright=135|thumb|Emperor Frederick I (middle) flanked by his two sons, Henry VI and Frederick VI. Year 1155 (MCLV) was a common year starting on Saturday of the Julian calendar