Unidentified Stamp

Unidentified Stamp
Arms:
Quarterly 1 & 4 Or a lion passant gardant on a chief a fleur-de-lys between two crosses patty fitchy 2 & 3. Within a bordure bezanty three [horses?] heads erased
Crest: A horse's head erased collared
Motto: Integra mens augustissima possessio
Dimensions (height x width): 38mm x 33mm
Quarterings: 1 & 4 Or a lion passant gardant on a chief a fleur-de-lys between two crosses patty fitchy 2 & 3. Within a bordure bezanty three [horses?] heads erase
Heraldic Charges: chief, on acrosses patty (2)fleur-de-lyshorse's headhorses heads (3)lion passant