Joan Shakespeare

Joan, John and Mary Shakespeare’s first child, was baptized on September 15, 1558, according to the Holy Trinity Church parish register. Next to the entry, an “X” added by a later hand highlights its significance. Stratford’s parish registers do not survive earlier than March 1558, but, given that Mary Shakespeare was single when her father, Robert Arden, made his will two years earlier in November 1556, there is no real doubt that Joan was her first child. Therefore, unless Mary was already pregnant at the time of her marriage to John Shakespeare, or Joan was born prematurely, we can date John and Mary’s marriage to mid-to-late 1557.

http://www.shakespearedocumented.org/exhibition/document/parish-reg...