The obligation to build bridges has a familiar place in the history of Anglo-Saxon governance because of its status as one third of the misnamed trinoda necessitas. Because the obligation has seemed to be such a matter of common sense, however, its purpose has by and large been taken for granted. In fact, bridge-work was not a straightforward phenomenon. A re-examination of the first appearance of bridgework in the charters of the early Anglo-Saxon period reveals that there were very few bridges and that the obligation appears sporadically in the charters rather than universally. It seems strange that kings insist upon bridge-work, when bridges seem not to have been important at all.

The Chronology of Bridge Building

The obligation to perform bridge-work appears in many Anglo-Saxon charters from the eighth century onwards. On the other hand, apparently paradoxically, the bounds listed in those same charters do not refer to many bridges. Indeed, the weight of evidence from charter bounds, from place-names, from the Anglo-Saxon Chronicle and from the formulae of the bridge-work clauses themselves, suggests that there were not many bridges in England until the tenth century.

In ninety-one authentic sets of charter bounds from the seventh, eighth and ninth centuries, only one bridge is mentioned, namely Crediton Bridge in Devon, which appears in the bounds of a charter of Æthelheard, king of Wessex, dating from 739. By contrast, there are fifty fords. The tenth century witnesses a change: the first quarter produced only nine genuine sets of bounds, which refer to one bridge and twelve fords; the second quarter produced 102 sets, referring to fourteen bridges, sixty-one fords; the third quarter, 173 sets, referring to forty-five bridges, ninety-six fords; the last quarter, forty-seven sets, containing seven bridges, twenty fords. Moreover, the presence of bridges in the bounds is accompanied by the frequent appearance of the term ‘old ford’. This phrase does not appear in a single genuine set of charter bounds before 945, but appears in thirteen sets after that date, suggesting that for the first time some fords that were still used as boundary markers were becoming redundant otherwise.