| A | B |
| Indulgence | Official pronouncement from the Church that reduced or erased the amount of time a person's soul would need to spend in purgatory; usually granted in exchange for a particular deed or sum of money |
| Excommunication | An order forbidding a person from receiving any holy sacraments, attending mass, being buried in sacred ground; it essentially barred him/her from the Church |
| Interdict | The excommunication of an entire region |
| Canonized | To be made a saint |
| St. Jerome | Translated the Old and New Testaments into Latin; his "Vulgate" translation became the Church's official Bibile |
| St. Augustine | Wrote The City of God in defense of Christianity |
| St. Patrick | Missionary in Ireland; devoted his life to preaching, baptizing people, and ordaining priests |
| St. Benedict | Founded an order of monks who lived by a set of strict rules |
| Refectory | The monastery's dining hall |
| Chapter House | The monastery's meeting hall |
| Monte Cassino | Monastery in Italy founded by St. Benedict |
| Pope Gregory I | Responsible for the conversion of many Anglo-Saxons in England to Christianity |
| Synod | A religious conference |
| Manuscript | Book copied out by hand |
| Scriptorium | Room in the monastery used for copying manuscripts |
| Illumination | Decorative designs or pictures added to manuscripts |
| St. Bede | English monk who wrote a history of the Church in England |
| jihad | An Arab term for "holy war" |
| Islam | Religion founded on "obedience to the will of Allah" |
| Muslim | A follower of the religious prophet Mohammed, a person who practices the Islamic religion |
| Mosque | A Muslim church |
| Moors | The Muslims who settled in Spain |