List of state leaders in 855

854 state leaders - Events of 855 - 856 state leaders - State leaders by year

Asia

• China (Tang Dynasty) - Xuanzong, Emperor of Tang China (846–859)
• Gurjara - Mihira Bhoja I, Pratihara King of Gurjara (c. 836–886)
• Japan (Heian Period) - Emperor Montoku, emperor of Japan (850–858)
• Korea (North South States Period)
  • Balhae - Dae Ijin, King of Balhae (830–857)
  • Silla - Munseong, King of Silla (839–857)

Europe

• Bulgaria - Boris I, Khan of the Bulgars (852–889)
• Byzantine Empire - Michael III (842–867)
• Caucasus
  • Principate of Iberia - Bagrat I Kuropalates (830–876)
  • Principality of Kakheti - Samuel, Prince of Kakheti (839–861)
• Kingdom of Denmark - Horik II (854–c. 866)
• England (Heptarchy) -
  • Kingdom of East Anglia - Edmund the Martyr (854–869)
  • Mercia - Burgred, King of Mercia (852–874)
  • Northumbria - Osberht, King of Northumbria (849–862/863)
  • Wessex - Æthelwulf, King of Wessex (839–856) and King of Kent (839–856)
• East Francia - Louis the German, King of East Francia (843–876)
  • Duchy of Saxony - Liudolf, Duke of Saxony (844–866)
  • Thuringia - Thakulf, Duke of Thuringia (849–873)
• Middle Francia - Lothair I, King of Middle Francia (843–855), King of Italy (818–855) and Holy Roman Emperor (817–855)
  • Littoral Croatia - Trpimir I, Duke of Littoral Croatia (845–864)
• West Francia - Charles the Bald, King of West Francia (843–877)
  • County of Angoulême - Turpion (839–863)
  • Duchy of Aquitaine - Ranulf I (854–866)
  • Kingdom of Aquitaine -
    • Pepin II of Aquitaine, King of Aquitaine (854–864)
      1. Charles the Bald, King of Aquitaine (838–855)
      2. Charles the Child, King of Aquitaine (855–866)
  • County of Barcelona - Odalric (852–858)
  • Duchy of Brittany - Erispoe (851–857)
  • Gascony - Sans II Sancion of Gascony, Duke of Gascony (836–864)
  • County of Maine - Rorgon II (853–865)
  • Poitiers - Ranulf I, Count of Poitiers (854–866)
  • County of Toulouse - Raymond I (852–863)
  • Troyes - Odo I, Count of Troyes (852–858)
  • County of Urgell - Solomon (848–869)
• Ireland - Máel Sechnaill mac Máele Ruanaid, High King of Ireland (846–862)
  • Ailech - Áed Findliath, King of Ailech (c. 855–879)
  • Connacht - Mugron mac Máel Cothaid, King of Connacht (848–872)
  • Uí Maine -
  • Leinster -
  • Kingdom of Mide - Máel Sechnaill mac Maíl Ruanaid (845–862)
  • Munster -
  • Kingdom of Osraige - Cerball mac Dúnlainge (842–888)
  • Ulaid - Matudán mac Muiredaig, King of Ulaid (839–857)
• Italy -
  1. Lothair I, King of Italy and Holy Roman Emperor (818–855)
  2. Louis II, King of Italy and Holy Roman Emperor (855–875)
  • Principality of Benevento - Adelchis (854–878)
  • County of Capua - Lando I (843–861)
  • March of Friuli - Eberhard (846–863)
  • Duchy of Gaeta - Constantine, Hypatus of Gaeta (839–866)
  • Duchy of Naples - Sergius I (840–864)
  • Papal States -
    1. Pope Leo IV (847–855)
    2. Pope Benedict III (855–858)
  • Principality of Salerno - Adhemar (853–861)
  • Duchy of Spoleto - Guy I (842–860)
  • March of Tuscany - Adalbert I (847–886)
  • Republic of Venice - Pietro Tradonico, Doge of Venice (836–864)
• Lotharingia - Lothair II, King of Lotharingia (855–869)
• Great Moravia - Rastislav, Prince of Great Moravia (846–870)
• Kingdom of Provence - Charles (855–863)
• Scotland
  • Picts - Kenneth I, King of the Picts (848–858)
• Serbia - Mutimir, Grand Zhupan of Serbia (850–891)
  • Strojimir, Zhupan of Serbia (850–856)
  • Gojnik, Zhupan of Rascia (850–856)
• Spain -
  • County of Aragon - Galindo Aznárez I (844–867)
  • Kingdom of Asturias - Ordoño I (850–866)
  • Caliphate of Córdoba - Muhammad I (852–886)
  • Kingdom of Pamplona - García Íñiguez (851/852–882)
• Wales -
  • Kingdom of Gwynedd - Rhodri the Great (844–878)
  • Kingdom of Powys -
    1. Cyngen ap Cadell (808–855)
    2. Rhodri the Great (855–878)

Middle East

• Abbasid Caliphate - Al-Mutawakkil (847–861)
• Byzantine Empire - Michael III (842–867)

Notes

In this year, Lothair I, Holy Roman Emperor and king of middle Francia, dies. His realm is partitioned for his three sons. Louis II becomes Holy Roman Emperor and king of Italy, Lothair II becomes king of Lotharingia and Charles becomes king of Provence.