List of state leaders in 1521

• Prince-Bishopric of Montenegro – Vladika German II (1520–1530)
• Duchy of Naxos – John IV Crispo (1517–1564)
• Ottoman (Turkish) Empire – Suleiman the Magnificent (1520–1566)
• Republic of Ragusa –
  1. Antun Bunić, Rector of Ragusa (1520–1521)
  2. Jako Bunić, Rector of Ragusa (1521–1522)
• Rhodes –
  1. Fabrizio del Carretto, Grand Master of the Knights Hospitaller (1513–1521)
  2. Philippe Villiers de L'Isle-Adam, Grand Master of the Knights Hospitaller (1521–1534)
• Principality of Zeta – Stjepan Berislavić (1514–1521)

• Kingdom of Hungary – Louis II (1516–1526)
  • Croatia – Ivan Karlović, Ban of Croatia (1521–1524)
  • Transylvania – John Zápolya, Voivode of Transylvania (1511–1526)
• Grand Duchy of Lithuania – Sigismund I the Old (1506–1548)
• Kingdom of Poland – Sigismund I the Old (1506–1548)

Holy Roman Emperor – Charles V (1519–1556)

• Principality of Anhalt-Dessau – Joachim I (1516–1544)
• Anhalt-Köthen – Wolfgang, Prince of Anhalt-Köthen (1508–1562)
• Prince-Bishopric of Augsburg – Christoph von Stadion (1517–1543)
• Margraviate of Baden-Baden – Bernard III (1515–1536)
• Margraviate of Baden-Durlach – Ernest (1515–1553)
• Margraviate of Baden-Sponheim – Philip I (1515–1533)
• Prince-Bishopric of Bamberg – Georg III Schenk von Limpurg, Bishop of Bamberg (1505–1522)
• Duchy of Bavaria – Louis X (1516–1545)
• Bentheim-Bentheim – Eberwin II, Count of Bentheim (1473–1530)
• Bentheim-Steinfurt – Arnold II, count of Bentheim-Steinfurt (1498–1544)
• Electorate of Brandenburg – Joachim I Nestor (1499–1535)
• Duchy of Brunswick and Lunenburg, Calenberg line – Eric I (1494–1544)
• Duchy of Brunswick and Lunenburg, Grubenhagen line –
  • Henry IV (1479–1526)
  • Philip I, ruled as Prince of Grubenhagen in other parts of that realm
• Duchy of Brunswick and Lunenburg, Wolfenbüttel line – Henry V (1514–1558)
  • County of Hoya – Jobst II (1507–1545)
• Bishopric of Cammin –
  1. Martin Karith (1499–1521)
  2. Erasmus von Manteuffel-Arnhausen (1521–1544)
• United Duchies of Jülich-Cleves-Berg –
  1. John II (1481–1521)
  2. John III (1521–1539), Duke of Jülich beginning in 1511.
• Electorate of Cologne – Herman V (1515–1546)
• Bishopric of Constance – Hugo von Hohenlandenberg(1496–1532)
• Prince-Bishopric of Freising – Philipp von der Pfalz (1499–1541)
• County of East Frisia – Edzard I the Great (1491–1528)
• County of Fürstenberg-Baar – Frederick III (1509–1559)
• Duchy of Guelders – Charles II (1492–1538)
• Landgraviate of Hesse – Philip I (1509–1567)
• Hohenzollern - Eitel Frederick III, Count of Hohenzollern (1512–1525)
• Duchy of Holstein – Christian II (1513–1523) and Frederick I (1490–1533) in condominial rule
• County of Holstein-Pinneberg – Antonius of Schaumburg (1510–1526)
• Königsegg – John IV, Baron of Königsegg (1500–1544)
• Prince-Bishopric of Liège – Érard de La Marck (1506–1538)
• Principality of Lippe – Simon V, Lord of Lippe (1511–1536)
• Duchy of Mecklenburg-Schwerin – Henry V, Duke of Mecklenburg (1503–1552)
• Mindelheim – Georg von Frundsberg, Lord of Mindelheim (1478–1528)
• Prince-Bishopric of Münster – Eric II, Duke of Saxe-Lauenburg (1508–1522)
• Nassau-Dillenburg - Henry III, Count of Nassau-Dillenburg (1516–1538)
• Nassau-Weilburg – Louis I, Count of Nassau-Weilburg (1492–1523)
• Nassau-Wiesbaden-Idstein – Philipp I, Count of Nassau-Wiesbaden-Idstein (1511–1558)
• Nassau-Saarbrücken - John Louis I, Count of Nassau-Saarbrücken (1472–1545)
• Palatinate-Neuburg – Otto Henry, Count Palatinate of Neuburg (1505–1559)
• Oettingen-Oettingen – Wolfgang I, Count of Oettingen-Oettingen (1467–1522)
• County of Ortenburg-Neuortenburg – Ulrich II (1495–1524)
• Prince-Bishopric of Osnabrück – Erich von Braunschweig-Grubenhagen, Prince-Bishop of Osnabrück (1508–1532)
• Prince-Bishopric of Paderborn – Erich von Braunschweig-Grubenhagen, Bishop of Paderborn (1508–1532)
• Duchy of Pomerania – Bogislaw X (1474–1523)
• Prince-Bishopric of Regensburg – Johann III von der Pfalz, Prince-Bishop of Regensburg (1507–1538)
• Electorate of the Palatinate – Louis V (1508–1544)
• Archbishopric of Salzburg – Matthäus Lang von Wellenburg (1519–1540)
• Duchy of Saxe-Lauenburg – Magnus I (1507–1543)
• Electorate of Saxony – Frederick III (1486–1525)
• County of Sayn – John IV (1498–1529)
• Schwarzenberg – Wilhelm I, Baron of Schwarzenberg (1510–1526)
• Stadion – John, Lord of Stadion (1507–1530)
• Electorate of Trier – Richard Greiffenklau zu Vollraths (1511–1531)
• County of Wied – John I (1487–1533)
• Zweibrücken – Louis II, Count Palatine of Zweibrücken (1514–1532)

• Duchy of Ferrara and Duchy of Modena and Reggio – Alfonso I d'Este (1505–1534)
• County of Guastalla – Achille Torelli (1494–1522)
• Margravate of Mantua – Federico II Gonzaga (1519–1540)
• Duchy of Massa and Carrara – Ricciarda Cybo-Malaspina, Marquis of Massa and Carrara (1519–1546)
• Duchy of Milan – Francesco II Sforza (1521–1524)
• March of Montferrat – Boniface IV (1518–1530)
  • Anne d'Alençon, Regent over Montferrat, mother of Boniface
• Papal States
  1. Pope Leo X (1513–1521)
  2. Pope Adrian VI 1521–1523
• Principality of Piombino – Iacopo V Appiani, Lord of Piombino (1511–1545)
• Duchy of Urbino – Francesco Maria I della Rovere (1508–1534)
• Marquisate of Saluzzo – Michele Antonio (1504–1528)
• San Marino –
  1. Andrea di Bonifazio, Captain Regent (1520–1521)
  2. Francesco di Girolamo Belluzzi, Captain Regent (1520–1521)
  3. Bartolomeo di Antonio Amanti, Captain Regent (1521)
  4. Bartolo di Simone Belluzzi, Captain Regent (1521)
  5. Cristofaro Martelli, Captain Regent (1521)
  6. Giacomo di Lodovico Calcigni, Captain Regent (1521)
• Duchy of Savoy – Charles III (1504–1553)
• Tuscany – Cardinal Giulio de' Medici, Archbishop of Florence
• Republic of Venice
  1. Leonardo Loredan, Doge of Venice (1501–1521)
  2. Antonio Grimani (1521–1523)

• Astrakhan Khanate – Qasim II (1504–1534)
• Cossack Hetamanate of Ukraine – Ostap Dashkevych, Hetman of the Cossacks (1506–1535)
• Crimean Khanate – Mehmed I Giray (1515–1523)
• Khanate of Kazan –
  1. Shahghali (1518–1521)
  2. Sahib I Giray (1521–1525)
• Grand Duchy of Moscow – Vasili III of Russia (1505–1533)
• Qasim Khanate – Canghali (1519–1531)

• Kingdom of Denmark and Norway – Christian II, King of Denmark and Norway (1513–1523)
  • Duchy of Schleswig – Christian II (1513–1523) and Frederick I (1490–1533) in condominial rule
• Kingdom of Sweden –
  1. Christian II (1520–1521)
  2. Gustav Vasa, viceroy (1521–1560)

• Kingdom of England – Henry VIII (1509–1547)
• Kingdom of France – Francis I (1515–1547)
• Monaco – Lucien, Lord of Monaco (1505–1523)
• Kingdom of Portugal and the Algarves –
  1. Manuel I (1495–1521)
  2. John III (1521–1557)
• Kingdom of Scotland – James V (1513–1542)
• Kingdom of Spain
  • Kingdom of Aragon – Charles I (1516–1556)
  • Crown of Castile
    • Queen - Joanna (1504–1555)
    • Regent – Charles I, King of Aragon (1556–1556)