"...Christian marriage involving two people of the same gender, before the redefinition?

There was no redefinition--- some progressive churches just began marrying people.... but here you go: http://en.wikipedia.org/wiki/History_of_same-sex_unions#Modern_times_2
(you can scroll UP to see historical instances)
No one 'redefined' anything... some countries & churches just began formally legalizing it after many years of Christian denominations refusing to recognize it. I don't see that being stubborn and bigoted constitutes a 'definition'.
In any case.... imagine someone you know and like explaining that they have just been legally married to someone of the same sex. What has changed in YOUR life since yesterday?

There's a small financial change for the government as benefits are granted, but I doubt that is your concern Ake.