The word 'had' — past tense and past participle of 'have' — descends from Old English 'hæfde,' the preterite of 'habban' (to have, to hold), from Proto-Germanic *habjaną, ultimately from PIE *keh₂p- (to seize, to grab). It shares the full etymological background of 'have' and 'has,' but its grammatical role in English gives it a distinctive story.
'Had' performs two distinct functions in Modern English. As a simple past tense ('I had a dog'), it expresses past possession or experience. As the pluperfect auxiliary ('I had gone before you arrived'), it marks an action completed before another past event. This double function makes 'had' one of the most temporally versatile
The formation of 'had' itself reveals something about how Germanic languages construct the past tense. The '-d' ending is the Germanic dental preterite suffix, one of the defining innovations of the Germanic branch. While other Indo-European languages formed past tenses through vowel alternation (ablaut), reduplication, or other mechanisms, Germanic developed a distinctive system using a dental consonant (-d or -t) added to the verb stem.
The origin of this dental suffix is debated, but the leading theory connects it to PIE *dʰeh₁- (to do, to place, to make), the same root that produced English 'do,' 'deed,' and the '-dom' suffix. Under this analysis, the earliest Germanic past tenses were periphrastic constructions: 'I love-did' (I did love) was compressed over time into 'I loved.' If this theory is correct, every regular English past tense — 'walked,' 'talked,' 'played' — contains a fossilized auxiliary verb meaning 'did,' fused into the main verb as a suffix.
The pluperfect use of 'had' ('had gone,' 'had seen') developed during the Old English period as a parallel to the present perfect ('has gone,' 'has seen'). Once 'have' grammaticalized into a tense auxiliary, it was natural to use its past tense 'had' to mark an earlier layer of pastness. This created the elegant English system where 'has gone' = completed action relevant to the present, and 'had gone' = completed action relevant to a past moment.
German 'hatte' (had), Dutch 'had,' and Old Norse 'hafði' all show the same dental suffix and the same dual function as simple past and pluperfect auxiliary, confirming that this grammatical pattern was already established in Proto-Germanic.