Origins
The history of 'sacrament' is a case study in how Christianity transformed the vocabulary of the Roman Empire, repurposing legal and military terms for theological ends. Latin 'sacrāmentum' had two primary meanings in classical usage, both rooted in the verb 'sacrāre' (to make sacred) and the adjective 'sacer' (sacred, holy — and, paradoxically, also accursed, set apart from normal human use).
The first meaning was legal. In Roman civil procedure, the 'sacrāmentum' was a sum of money that both parties in a lawsuit deposited with a third party or in a temple; the loser forfeited their deposit to the state. The term derived from the idea that the money was 'made sacred' — consecrated, placed beyond ordinary use — as a guarantee of good faith. This was one of the oldest forms of Roman litigation, predating the Republic.
The second meaning was military. The 'sacrāmentum' was the oath of allegiance sworn by Roman soldiers upon enlistment, binding them to their commander and to Rome under divine sanction. Breaking the oath was not merely desertion but sacrilege — a violation of the sacred bond. This sense gave 'sacrāmentum' its deepest connotation: an act that placed the participant under divine obligation, transforming an ordinary commitment into something sacred and inviolable.
Latin Roots
The Christian adoption of the word was both deliberate and transformative. The earliest known Christian use of 'sacrāmentum' in a theological sense appears in the writings of Tertullian (c. 155-220 CE), who used it to translate the Greek word 'mystērion' (μυστήριον, mystery). Greek-speaking Christians had used 'mystērion' — borrowed from the mystery religions — to describe the hidden realities of the faith made visible through ritual. Tertullian's choice of 'sacrāmentum' as the Latin equivalent was brilliant: it preserved the sense of sacred obligation from the military oath while adding the element of divine mystery from the Greek.
The great theologian Augustine of Hippo (354-430) developed the concept further, defining a sacrament as a 'visible sign of invisible grace' — a formula that has influenced Christian theology ever since. Augustine's definition established the essential structure of sacramental thinking: an outward, material action (water, bread, wine, oil) serves as the vehicle for an inward, spiritual reality.
The word entered Old French as 'sacrament' and was borrowed into Middle English in the twelfth century. In medieval Christendom, the number of sacraments was debated until the Fourth Lateran Council (1215) and the Council of Florence (1439) confirmed seven for the Roman Catholic Church: baptism, confirmation, Eucharist, penance, anointing of the sick, holy orders, and matrimony. The Protestant Reformation reduced this to two — baptism and the Eucharist (or Lord's Supper) — arguing that only these had explicit warrant in the New Testament.
Later History
The Reformation debates over the sacraments were among the most consequential theological controversies in European history. Luther, Calvin, and Zwingli disagreed sharply with each other about what happened during the Eucharist — whether Christ was physically present in the bread and wine, spiritually present, or symbolically represented. These disagreements fractured Protestantism into multiple traditions and shaped European politics for centuries.
In modern English, 'sacrament' retains its primary theological meaning but has developed secular extensions. To describe something as 'sacramental' is to suggest that it carries meaning beyond its material form — that the visible act embodies an invisible significance. Writers speak of 'the sacrament of ordinary life,' 'sacramental attention,' or 'sacramental imagination,' using the word to suggest that material reality can be a vehicle for transcendent meaning.
The deeper etymological family is rich. Latin 'sacer' (sacred) produced 'sacrifice' (to make sacred by killing), 'sacrilege' (theft of sacred things), 'sacrosanct' (inviolably sacred), 'consecrate' (to make thoroughly sacred), and 'desecrate' (to un-sacred, to profane). The Proto-Indo-European root *sak- (to sanctify) may also be connected to Hittite 'saklai' (rite, custom), suggesting that the concept of the sacred and its ritual expression has been linguistically linked since the earliest recoverable stage of the language family.