IntheconflictsbywhichthecountrywasdistractedafterthedepartureoftheRomans，eachsuccessfulcompetitorexactedfromthosehehadsubdued，anoathoffidelityandsubmission。
Fromthispracticetheusagearoseofrequiringasimilarengagementfromtheirownfollowers，astheysubsequentlydispersedthemselvesthroughthecountryandwhenHaroldwasoverthrownbytheBastardofNormandy，thenecessityofexactingitbecamemoreobvious，notonlyfromthediscontentwhichhisseveritiesexcited，butfromtheimpressionwhichtheillegitimacyofhisbirthmightmakeonhissubjects。
Theoathoffealtyandhomagenecessarilyaccompaniedthenumerousgrantsofland，wrestedfromitsoriginalowners，andbestoweduponhisadherents；
theoathofallegiancewasincorporatedwiththeoathoffealty，andwhoeverwillreflectontheconditionofthetimeswillbesatisfiedthatallegiancewasnotsworntothenation，buttotheindividualwhosevictoriousarmshadrenderedhimtherulerofthenation。
Hencecertainconsequenceswereunderstoodtoflow；theallegiancethussolemnlypledgedcouldnotbewithdrawn，unlesstheprotectionwhichwasimpliedinreturn，shouldbewithheldorbecomeimpracticable。