Anglo-Saxon Institutions. 449-1066 69
cannot be told. Surely the kings were not trying to make
these pledge-groups universal and compulsory as they
were the tithings. But the two began to merge, probably
from about 1030. They were bound to do so once they
were side by side, for the groups were sure to overlap or
coincide in personnel and their duties bore a close rela-
tion. ^ The supposed criminal which the tithing must pur-
sue might be one of the tithing which, under the aspect
of pledge-group, it was bound under heavy fine to present
in court. How far the merging went before the Conquest
we cannot say, but not in the Anglo-Saxon period had the
king or any other authority made the pledge-groups uni-
versal or an absolutely binding obligation. There was
something voluntary about them to the end of the period.
But these institutions are striking instances of public re-
sponsibility resting upon the people. They are the
germs of ^ the later frankpledge, one of the most curious,
characteristic, and in many ways important of English
local institutions.I
A duty resting upon all free Englishmen of this period,
and which goes back no one knows how far, is that often
referred to as the trinoda necessitas, the threefold obliga-
tion. The first was the duty of serving in the militia,
a public service which the citizen owed the state. By the
later period this was, no doubt, in some degree territorial-
ised,2 that is, in practice, a fixed, traditional number was
required from certain districts or holdings; but theoretic-
ally and in times of need it was probably still enforcible
on the individual freeman. Second, was the duty of
keeping in repair the nearby fortress or occasionally of
building a new one; and third, the repair or building of
bridges. These duties were enforced against the thegns
as well as the common freemen, and very rarely was any-
one exempted.
The thegns, beyond the trinoda necessitous, owed a
1 On the whole subject of the frankpledge, see W. A. Morris, The Frank-
pledge System,
2 See above, p. 18, note i, and below, pp. 97, 98. One man to one hide
of land was supposed to be something of a norm in England,