Nicholas I
# Nicholas I

Nicholas I may refer to:

* Pope Nicholas I (c. 800–867), or Nicholas the Great
* Nicholas Mystikos (852–925), Patriarch Nicholas I of Constantinople
* Nicholas I (bishop of the Isles) (fl. 1147–1152), Bishop-elect of the Isles
* Nicholas I, Lord of Mecklenburg (died 1200)
* Nicholas I of Transylvania (died after 1203), voivode of Transylvania
* Nicholas I (bishop of Schleswig) (died 1233)
* Patriarch Nicholas I of Alexandria, Greek Patriarch of Alexandria between 1210 and 1243
* Nicholas I, Duke of Troppau (c. 1255–1318), natural son of king Ottokar II of Bohemia, became Duke of Troppau in Silesia
* Nicholas I, Lord of Rostock (died 1314)
* Nicholas I, Count of Tecklenburg (died 1367)
* Nicholas I Garai (died 1386), chief governor of Bratislava, palatine to the King of Hungary
* Nicholas I of Opole (c. 1424–1476)
* Nicholas I, Duke of Lorraine (1448–1473)
* Nicolaus I Bernoulli (1687–1759); Swiss mathematician
* Nicholas I, Prince Esterházy (1714–1790), Hungarian prince
* Nicholas I of Russia (1796–1855), Emperor of Russia and King of Poland
* Nikola I Petrović-Njegoš (1841–1921), King of Montenegro
