An entry in the Stratford Parish baptismal register reads written in Latin, "Gulielmus filius Johannes Shakspere" William son of John Shakespeare.
(Registers of the 16th and 17th centuries were often written in Latin, they could be in Latin or English at this time.)
At some point some one has put an "X" against Shakespeare baptism and death entries.
(Stratford Parish Register of Holy Trinity Church, f. 5.)
Extract of the above showing just Shakespeare's baptism entry