- Jews--Dietary laws1
- Job (Biblical figure)1
- John, the Apostle, Saint1
- Judaism (Christian theology)1
- Judaism--Prayers and devotions1
- Julian, of Eclanum, Bishop, 380-approximately 4551
- Julii family1
- Justinian I, Emperor of the East, 483?-5651
- Kapitalbünde1
- Kings and rulers--Succession1
- Kinot1
- Knights and knighthood1
- Labyrinths1
- Lamucci, Corso1
- Landlord and tenant1
- Language and languages1
- Language and languages--Philosophy1
- Lanvers, Hamo1
- Lapidaries (Medieval literature)1
- Lathom, Robert de, 13th century1