I have been thinking about this for a while. It seems to me that, sometimes, the subject plays a dative role in that it is the recipient of something. Take the following active sentence.
He gave me a gift.
If it is made passive, it normally changes as follows.
A gift was given to me (by him).
In which case a gift is clearly nominative and to me clearly dative. However, I often see the following passive construction used instead.
I was given a gift (by him).
In which case I appears to be a sort of nominative-dative, yet I can't quite explain a gift or what it does in the sentence; it is certainly not accusative. Semantically, I understand the sentence, but I cannot make syntactic sense of it.
After a quick search on Google Ngram, it seems that gift was given me is the oldest possible construction, which makes sense, followed by gift was given to me, which also makes sense. The first instance of I was given a gift appears to be in 1920, from which point it has risen steadily. So it seems quite obvious that it is a new usage.
Is this a 'correct' usage, so to speak? How did it come about? Most interestingly to me, how is it explained grammatically? Can it be adequately explained with traditional grammatical terms? or does it require an altogether new analysis?