A libellus (plural libelli) was a document given to a Roman citizen to certify performance of a pagan sacrifice, hence demonstrating loyalty to the authorities of the Roman Empire. They could also mean certificates of indulgence, in which the confessors or martyrs interceded for apostate Christians.
"Forty-six such certificates have been published, all dating from this same year [250 AD]." This particular year falls into the period of persecution under the emperor Decius. Four libelli were found among the thousands of papyri at the archaeological site near Oxyrhynchus in Egypt (POxy 658, POxy 1464, POxy 2990 and POxy 3929).
Participating in pagan sacrifices was a sin for Christians and punished by excommunication, because the New Testament forbade Christians to either participate in "idol feasts" or to eat "meat sacrificed to idols". However, not participating made one liable to arrest by the Roman authorities. A warrant to arrest a Christian (POxy 3035) was also found at Oxyrhynchus, this too has been dated precisely—to the year 256. The grounds for this arrest are not documented, however, and it predates the persecution under the emperor Valerian by about a year.
At various times under Roman rule, failure to sacrifice was punishable by death. Christian theologians (for example Cyprian) debated whether the threat of the death penalty mitigated the sin of having communion with idols, leaving room for forgiveness and restoration to the Christian community. The unresolved debate became moot when the emperor Constantine I became a Christian (early 4th century).
The word libellus is a Latin diminutive form of the ordinary word liber (meaning book), from which we get the English word library. Literally, it means "little book." Sometimes the word was used to describe what we would call: essays, tracts, pamphlets, or petitions.
- "Libellatici, Libelli". Catholic Encyclopedia. New York: Robert Appleton Company. 1913.
- 'Certificate of pagan sacrifice: June - July, AD 250', Oxyrhynchus Papyri Project, Oxford University.