(see eventually J)
- Ibycus (Ibicus): 917, 2056.
- Ignatius of Antiochia (saint): 1102, 1435, 1436, 1437, 1438, 1439 .
- Ignatius of Loyola (saint): 1217, 2140, 2141.
- Ilingius, Joannes: 1219.
- Infantius, Carolus: 1286.
- Iniguez a Lequerica, Joannes (publisher in Alcala): 1239.
- Innocentius I (pope): 1333.
- Innocentius VIII (pope): 1315, 1316, 1317.
- Intosanus a Fraxinis, Nicolaus: 1512.
- Irenaeus: 927.
- Isaac Levita, Joannes: 1456, 1457 , 1863.
- Isaacus, Stephanus: 1457.
- Isabella (daughter of Philip II): 690, 1945, 2228.
- Isabella Austriae (queen of France): 606.
- Iselstein, Florentius (baron of Iselstein): 11, 14.
- Iselsteinus, Maximilianus: 625.
- Isengrinius, Michael (publisher in Basel): 993.
- Isidorus (saint): 1221.
- Islip, Adam (publisher in London): 842.
- Isocrates: 1286, 1458, 1459 , 1966, 2305, 2306.
- Istuans, Nicolaus: 2168.
- Iue (Ive), Fridericus d': 1407.
- Ivan IV (tsar of Russia [Muscovy]): 1516, 2094.
- Ivellus: 1472.