<Tr> <Th> Adopted </Th> <Td> 19th century </Td> </Tr> <Tr> <Th> Design </Th> <Td> A white cross on a black background . </Td> </Tr> <P> Saint Piran's Flag (Cornish: Baner Peran) is the flag of Cornwall, England, United Kingdom . The earliest known description of the flag as the Standard of Cornwall was written in 1838 . It is used by some Cornish people as a symbol of identity . It is a white cross on a black background . </P> <P> The flag is attributed to Saint Piran, a 6th - century Cornish abbot . One early use of a white cross and black background design is the 15th - century coat of arms of the Saint - Peran family . </P>

What flag is black with a white cross