A short reference
The words that recur across relics, thecae and their documents — from authentica to theca — defined plainly, in the order you meet them.
Three terms sit inside one another and are often confused. The diagram below shows how they relate: a relic and its cedula sit within a theca, which in turn sits within a reliquary.
How the terms nest
relic & cedula · theca · reliquary
The glossary
Authentica (authentica)
The certificate that authenticates a relic — a testimonial letter from a bishop, cardinal vicar, postulator or custodian of relics, sealed and signed.
Cardinal Vicar of Rome
The pope's delegate for the diocese of Rome; the Vicariate under him issued a great many authenticae for relics distributed from the city.
Cedula (cedula)
The small paper label placed with the relic inside a theca, naming the saint and the type of relic in abbreviated Latin.
Corpisanti / Catacomb saints
Relics recovered from the Roman catacombs, widely identified and distributed across Europe in the 17th and 18th centuries.
Ex ossibus (ex ossibus)
“From the bones” — the most common of the Latin formulae naming a relic's type. See the article on Latin abbreviations.
First / Second / Third class
The three-part devotional taxonomy of relics: the body of a saint; something they owned or used; and an object touched to a higher-class relic.
Insignis (insignis)
A “notable” relic — a whole limb or the head — as distinct from a small particle. A size distinction, not a separate class.
Lipsanotheca (lipsanotheca)
A collection or repository of sacred relics (from the Greek leipsanon, relic).
Monstrance / Ostensorium (ostensorium)
A vessel with a viewing window used to display a relic — or the Host — for veneration.
Postulator (postulator)
The official who promotes a cause for canonisation and who may be authorised to authenticate and distribute relics.
Reliquary
The container, frame or monstrance that houses a relic or theca for veneration or display.
Reliquiae (reliquiae)
Latin for “relics” — the remains or objects themselves.
Sigillum (sigillum)
The wax seal impressed by the issuing authority's signet, closing the theca and matching the seal on the authentica.
Spanish wax
The red sealing wax traditionally used to close the reverse of a theca over its silk cords.
Theca (theca)
The small sealed vessel — brass, gilt or silver, glazed at the front — that actually holds the relic within a reliquary.
These are working definitions as the terms are commonly used among collectors and dealers. Usage has varied across regions and centuries, and a single word can carry slightly different senses in a scholarly, liturgical or trade context.