Definition
Tempus pessonis is a Latin legal phrase from English forest law meaning "mast-time" — the seasonal period during which swine were permitted to be driven into royal forests to feed on fallen acorns, beechnuts, and other mast (the fruit of forest trees). The period ran roughly from Michaelmas (September 29) to Martinmas (the feast of St. Martin, November 11), a span of approximately six weeks in the autumn. During this time, the right of pannage — the privilege of pasturing pigs in the forest — was exercised, typically under license from the Crown or the relevant forest authority, and subject to the payment of dues.
Why It Matters in Research
This is a term of English forest law with no modern survival in common legal usage. Researchers encountering it will almost always be working with medieval or early modern sources — forest court records, eyre rolls, manorial documents, grants of common rights, or treatises on the common law of forests. The term operates within a dense cluster of related forest law vocabulary (pannage, agistment, herbage, mast), and understanding its precise seasonal boundaries matters when interpreting disputes about timing, trespass, or the scope of a granted right.
The dates — Michaelmas to Martinmas — are liturgical calendar markers, not fixed calendar dates in the modern sense. Researchers using document-dating conventions of the period should be alert to this. The period also overlapped with other forest law seasons that governed different uses and different officers, so misidentifying which seasonal right is at issue can lead to misreading a source document entirely.
Tempus pessonis does not appear in most general legal dictionaries of the nineteenth century; its absence from standard reference works means researchers may find it only in specialized forest law treatises or glossaries appended to historical records editions. Cowell's Interpreter, cited by Rapalje & Lawrence, is the primary historical glossary source for this term and related forest law vocabulary.
Historical Dictionary Support
Rapalje & Lawrence reproduce the definition essentially from Cowell (John Cowell, The Interpreter, first published 1607), identifying tempus pessonis as "mast-time in the forest, which is about Michaelmas to St. Martin's Day, November 11th." The qualifier "about" in Cowell's original reflects that the precise start and end of the pannage season could vary by forest, by local custom, and by the condition of the mast in any given year — a practically important caveat that later summary treatments sometimes drop.
Rapalje & Lawrence append to this entry a separate though related term, tempus semestre, defined as "half a year, and not six lunar months," with a citation to Westminster II, chapter 5. The juxtaposition in the original dictionary entry appears to be alphabetical convenience rather than substantive connection; the two terms are distinct in subject matter and legal context. Researchers should not infer that tempus pessonis carried a half-year duration — the pannage season was far shorter.
No significant divergence appears across the historical sources on the core meaning; the term is narrow and technical enough that there was little occasion for interpretive dispute in the dictionaries. What the historical dictionaries collectively fail to provide is context about enforcement — the forest courts, the agisters who managed the season, and the dues structure — which must be sought in primary forest law sources such as Manwood's Treatise of the Forest Laws (1598, expanded 1615) or the historical records of specific royal forests.
Jurisdictional Note
Tempus pessonis is a term of English forest law specifically. It has no recognized parallel in Scots law, Irish law, or American law. Researchers outside the English forest law tradition will not encounter it in operative legal sources.