<Li> <P> A "Vinegar Valentine" card from the 1870s, with a red heart symbol pierced by six arrows . </P> </Li> <P> A "Vinegar Valentine" card from the 1870s, with a red heart symbol pierced by six arrows . </P> <Li> <P> The traditional "heart shape" appears on a 1910 Valentine's Day card . </P> </Li> <P> The traditional "heart shape" appears on a 1910 Valentine's Day card . </P>

Where did the symbol of the heart come from