TRINODA

NECESSITAS  , the name used by modern historians to describe the threefold obligation of serving in the host (fyrd), repairing and constructing bridges (bryc-geweorc), and the construction and maintenance of fortresses (burhbot), to which all freeholders were subject in Anglo-Saxon times . The obligations are usually mentioned in charters as the sole exceptions to grants of immunities; sometimes, however, a fourth obligation (singalare praeiium contra (ilium) is reserved, as in the charter granted by Wiglaf of Mercia on the 28th of December 831 (Cod. dip. i . 294) . Ceolwulf's charter of 822 to Arch-bishop Wilfred is remarkable, as the military service is there restricted to expeditiones contra paganos ostes (ibid. i . 272) . The threefold obligation is first mentioned in a Latin charter (expeditions pontis arcisue constructione) of doubtful authenticity, which professes to have been granted by Eadbald of Kent in A.D . 626 (Cod. dip. v . 2), but it is not until the 8th century that it appears in documents which are generally admitted to be genuine . Although there were corresponding obligations in the Frankish Empire which were called by Charles the Bald (antiquam et aliarum gentium consuetudinem), Stubbs held that the arguments which refer them to a Roman origin want both congruity and continuity . The phrase " trinoda necessitas " is not to be found in the Anglo-Saxon laws and charters; and Selden was probably the first historian of eminence who used it . " These three exceptions," he says, " are noted by the term of a three-knotted necessity in an old charter wherein King Cedwalla granted to Wilfrid, the first bishop of Shelsey in Sussex, the village of Paganham." This charter is an 1th-century copy of a lost original, but the words to which Selden referred are plainly written as trimoda necessitas not irinodanecessitas . Du Cange gives two examples of the word trimoda in medieval Latin, in which language it meant " triple "; but he cites no medieval example of trinoda; and in classical Latin the form is unknown, while trinodis (ter-nodus, " triple-knotted ") occurs only rarely (Ovid .

Her. iv . 115; Fast. i . 575) . See Du Cange, Glossarium; W . Stubbs, The Constitutional

History of England, i . 86, 87; J . M . Kemble, Codex anglo-saxonicus, passim; Selden, English Janus (London, 1682), p . 43; Walter de Gray Birch, Cartularium saxonicum, passim; Facsimiles of Ancient Charters in the British Museum, pt. iv . Cotton MS . Augustus, ii . 86 .

(G . J .