See:

• Ferdinand I of Castile and Leon , the Great (ca. 1000-1065, king from 1037)
• Ferdinand I of Portugal and the Algarves (1345-1383, king from 1367)
• Ferdinand I of Aragon and Sicily, the Just (1379-1416, king from 1412)
• Ferdinand I of Naples (ca. 1424-1494, king from 1458)
• Ferdinand I of Germany (1503-1564, king of Hungary and Bohemia from 1526, emperor from 1556)
• Ferdinand I of Tuscany (1549-1609, grand-duke from 1604)
• Ferdinand I of Parma , Plaisance and Guastalla (1751-1802, duke from 1765)
• Ferdinand I of the Two Sicilies (1751-1825, king of Naples from 1759, of Two Sicilies from 1816)
• Ferdinand I of Austria (1793-1875, emperor 1835-1848)
• Ferdinand of Bulgaria (1861-1948, prince 1887-1908, tsar 1908-1918)
• Ferdinand of Romania (1865-1927, king from 1914)