Trinoda necessitas
Template:Short description Template:Use dmy dates Trinoda necessitas ("three-knotted obligation" <ref>Template:Cite book</ref> in Latin) is a term used to refer to a "threefold tax" in Anglo-Saxon times. Subjects of an Anglo-Saxon king were required to yield three services: bridge-bote (repairing bridges and roads), burgh-bote (building and maintaining fortifications), and fyrd-bote (serving in the militia, known as the fyrd). Rulers very rarely exempted subjects from the trinoda necessitas, because these services were the lifeblood of an Anglo-Saxon kingdom.<ref>Template:Cite book</ref><ref>Template:Cite book</ref> After the Norman Conquest, exemptions from the trinoda necessitas became more common.<ref name=Hollister/>
The term "trinoda necessitas" was rarely used in Anglo-Saxon times: its only known use is in a grant of land near Pagham, Sussex from King Cædwalla of Wessex to Saint Wilfred.<ref name=stevenson>Template:Cite journal</ref> The Wilfred grant used the term trimoda (Latin for "triple"); trinoda (Latin for "triple-knotted") was an error introduced by John Selden in 1610.<ref name=stevenson/><ref name=eb1911>Template:Cite EB1911</ref>
Instead of the term "trinoda necessitas", it was common for Anglo-Saxon land grants to spell out the three obligations individually. For example, the land grant of Æthelberht of Kent to a thegn in 858 was free of obligation, except explicitly for military service, bridge repair, and fortification.<ref name=Hollister>Template:Cite book</ref>