I have a beautiful blue and white, very large, very heavy platter. My grandmother told me that her mother told her, George Washington was served from this platter. It is a lily pattern. Lillies around the rim and on the serving bottom of the platter. On the back, a "modified"?? English Crown with a lion (mans face) on the left and a Unicorn on the right. There is a 'makers mark'.. JT. The word "Lily" is also on the back of the platter. I have searched everywhere I possibly can find online, and every antique shop I see and have never found another piece with this Lily Pattern... Does anyone have any information on this pattern?

Please post photos.

The lion and unicorn mark is everywhere, used by the English first (British coat of arms) and Americans second, sometimes to just look English. It is a mark of Staffordshire pottery. Since you say it's heavy, it's probably ironstone.
American potters used the mark without any company name at first, but that started in the late 1800s, past Washington's time.

(yes, you must take good clear photos, of the front and back and a close up of the pattern. The pattern varies a lot, and you need to show it to experts to see if it's hand painted or a transfer, and so on.)

Unless you have written proof that GW was served from this platter, it is pretty meaningless. You need provenance to "claim GW ate here"!