The official calendar of the Republic of the Philippines: an almanac of Philippine commemorations enlivened with illustrations and information. –Manila: Presidential Communications Development and Strategic Planning Office, .
On this day in 337 AD, Constantine the Great was baptized and converted to Christianity before his death.
On this day in 1906, the brothers Orville and Wilbur Wright were granted a patent for their Airplane Technique which they flew on December 17, 1903.
Today, May 22 is International Day for Biological Diversity.