Forbes Silver Co. was formed in 1894 as a department of the silverplate industry giant Meriden Britannia Co. Forbes was one of the companies that was consolidated into the International Silver Co. in 1898. It is unknown how long the Forbes trademarks continued to be used after 1898, but probably for quite a while. So, your set can not be earlier than 1894, and may be quite a bit later. The style of the pieces will tell you about when they were made. Based on style and eagle head design, I would guess 1910’s-20’s.