Party invitations c.1900-20.

Party invitations c.1900-20. These came together and I thought I’d keep them together. They came from my friend in Yorkshire who used to be an auction consultant and, as I’ve said elsewhere, I’m always pleased to buy from him. In looking at and enjoying ephemera for 60 years I don’t remember seeing party invitations before. Perhaps I was looking in the wrong places.
These may be intended for children’s parties but I tell myself that they’d have been amusing for adolescents and adults of the right disposition.
The biggest card is 5 x 4 inches and I may as well call it number 1.
1) c.1920. Unused.
2) “Shall be delighted to come.” C.1900-10. Unused. A little foxing.
3)  “Accepted with best thanks.” Similar to 2).
4) “Such Fun.” Sent and dated 1904.
5) Sent but not dated. A little grubby: cake stains?
Other ephemera from this period on my website include: Fold-out cards, c.1910. but I don’t have any more party invitations.
I’ve looked online and there are some invitations on eBay http://eBay.co.uk but they all seem to be a bit later. I’m sure that there must be collections of them but perhaps they are as unusual as I think they are.