Joan Shakespeare was the second child born to John and Mary, named after a sister who had died shortly after birth. 
Per information obtained on https://archive.is/wuaaw#selection-701.2-701.631 : She was named after the first daughter that died in infancy..-- Due to the fact that Shakespeare's children and his other siblings did not carry on the line past the seventeenth century, the descendants of Joan Shakespeare Hart possess the only genetic link to the great playwright. Joan Shakespeare's husband died 1616 and she lived the rest of her life in Shakespeare's birthplace. She died in 1646, but her descendants stayed in Stratford until 1806.
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