Famous Birthdays Apr 5 Vincenzo Viviani, Italian mathematician (Viviani's theorem), born in Florence, Italy (d. 1703) Apr 7 Louise Hollandine, daughter of King Frederik V & Elizabeth Stuart Apr 17 Henry Vaughan, English poet (Silex Scintillans), born in Newton St. Bridget, Brecknockshire, Wales (d. 1695) Famous Deaths Apr 24 Fidelis of Sigmaringen, Swiss friar, martyr, and saint, dies at 44 1621 History by Year 1623