I would say this is Edwardian because of the style though again I could be wrong. Either way it is a stunningly beautiful wedding dress and I'm sure the bride who wore this was extremely lucky.
The first noticable thing for me is the exquisite train that flows behind the dress and take up most of the display, I'd say it's made of some heavy kind of silk or velvet. It's absolutely beautiful but I'm sure it was murder for the bridesmaids to hold! The sleeves are long and have a cuff with lace or something on them, the top of the sleeves where the shoulder would be have a kind of ribbon pin-tuck/concertina look to them. Then we come to another exquisite piece, the neck. It's a beautiful neck piece made of lace nad runs over the tips of the shoulders, between the shoulders and up to the neck. (I'll upload the detailed photo too)
The bodice is slim and fitted with swirls of fabric gathered all around the top of the bodice. There also appears to be some fabric/lace flowers attached to the right (on the picture) side of the bodice. You then have the skirt which seems to be seperate from the bodice, it's rather plain but still beuatiful it flows well and leads onto that magnificent train.
EDIT - Pre Edwardian possibly - 1890s
From Bath Fashion Museum