Definition
A Latin term appearing in old English law denoting a sack — specifically, a standard unit of measurement for wool. A saoccus represented a quantity of wool weighing either twenty-eight or thirty stone, depending on the source and period. The term functioned as a unit of commercial measure in the medieval English wool trade rather than as a legal concept in its own right.
Why It Matters in Research
Researchers are most likely to encounter saoccus in medieval English commercial records, customs documents, and treatises on weights and measures rather than in case law or statutory material. The term is essentially a lexical artifact of the wool trade, which was among the most economically significant industries in medieval England and generated its own dense vocabulary of measure.
The inconsistency in the recorded weight — twenty-eight or thirty stone — is itself a research signal. Weights and measures in pre-modern England were notoriously unstandardized and varied by commodity, locality, and period. A document specifying a saoccus of wool cannot be assumed to reflect a fixed quantity without reference to the specific time and place of the transaction. Researchers working with manorial accounts, customs rolls, or export records should treat the term as indicating a bulk sack unit of wool while remaining alert to local variation in the actual weight intended.
The term appears in Fleta, a late thirteenth-century Latin legal treatise, which is the primary source Black's relies upon. Fleta is a significant but specialized corpus source — it draws heavily on Bracton and is associated with the circle of Edward I's judges. Its treatment of commercial measures reflects the administrative and fiscal concerns of the Crown over the wool trade, particularly in the context of customs duties. Researchers using Fleta should be aware that the text exists in manuscript form and that editorial decisions in published editions can affect how numerical values like weights are transcribed.
Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) provides the only dictionary entry for this term in the Law Mind corpus. The definition is brief: a sack, a quantity of wool weighing thirty or twenty-eight stone, citing Fleta, book 2, chapter 79, section 10. Black's does not elaborate on the discrepancy in weight or explain the commercial context.
The entry is consistent with what is known from other historical sources about the English wool sack as a unit of measure. The woolsack — familiar today as the ceremonial seat of the Lord Chancellor in the House of Lords — is a direct cultural descendant of the same commercial unit. The sack of wool was the standard unit for customs assessment under the Magna Carta wool customs and the later maltolt, which underscores the fiscal importance of having a defined (if not always consistent) unit of weight.
Historical dictionaries of weights and measures, such as those compiled by scholars of English metrology, generally place the wool sack at 26 stone (364 pounds) in later standardized usage, though earlier periods show variation. The discrepancy between Black's figures of twenty-eight and thirty stone and the later standard of twenty-six stone illustrates how measures evolved — and why researchers should not back-project later standardized values onto earlier documents.
Jurisdictional Note
Saoccus is a term of old English law with no modern jurisdictional application. It is relevant exclusively to historical English legal and commercial records, primarily from the medieval period.