| 51601 | May.04 | Death | 2013 – César Portillo de la Luz, Cuban guitarist and composer (b. 1922) |
| 51602 | May.04 | Death | 2014 – Dick Ayers, American author and illustrator (b. 1924) |
| 51603 | May.04 | Death | 2014 – Elena Baltacha, Ukrainian-Scottish tennis player (b. 1983) |
| 51604 | May.04 | Death | 2014 – Edgar Cortright, American scientist and engineer (b. 1923) |
| 51605 | May.04 | Death | 2014 – Helga Königsdorf, German physicist and author (b. 1938) |
| 51606 | May.04 | Death | 2014 – Ross Lonsberry, Canadian-American ice hockey player (b. 1947) |
| 51607 | May.04 | Death | 2014 – Jean-Paul Ngoupandé, Central African politician, Prime Minister of the Central African Republic (b. 1948) |
| 51608 | May.04 | Death | 2014 – Tatiana Samoilova, Russian actress (b. 1934) |
| 51609 | May.04 | Death | 2015 – William Bast, American screenwriter and author (b. 1931) |
| 51610 | May.04 | Death | 2015 – Ellen Albertini Dow, American actress (b. 1913) |
| 51611 | May.04 | Death | 2015 – Marv Hubbard, American football player (b. 1946) |
| 51612 | May.04 | Death | 2015 – Andrew Lewis, Guyanese boxer (b. 1970) |
| 51613 | May.04 | Death | 2015 – Joshua Ozersky, American historian, journalist, and critic (b. 1967) |
| 51614 | May.04 | Holiday and observance | Anti-Bullying Day (United Nations) |
| 51615 | May.04 | Holiday and observance | Bird Day (United States) |
| 51616 | May.04 | Holiday and observance | Cassinga Day (Namibia) |
| 51617 | May.04 | Holiday and observance | Christian feast day:Blessed Ceferino Giménez MallaEnglish Saints and Martyrs of the Reformation Era (Church of England)F. C. D. Wyneken (Lutheran Church–Missouri Synod)FlorianGotthard of HildesheimJudas CyriacusSaint MonicaSacerdos of LimogesVenerius of M |
| 51618 | May.04 | Holiday and observance | Day of the adoption of the Declaration of independence (Latvia) |
| 51619 | May.04 | Holiday and observance | Death of Milan Rastislav Štefánik Day (Slovakia) |
| 51620 | May.04 | Holiday and observance | Greenery Day (Japan) |
| 51621 | May.04 | Holiday and observance | International Firefighters' Day |
| 51622 | May.04 | Holiday and observance | May Fourth Movement commemorations:Literary Day (Republic of China)Youth Day (China) |
| 51623 | May.04 | Holiday and observance | Remembrance Day for Martyrs and Disabled (Afghanistan) |
| 51624 | May.04 | Holiday and observance | Remembrance of the Dead (Netherlands) |
| 51625 | May.04 | Holiday and observance | Star Wars Day |
| 51626 | May.04 | Holiday and observance | Youth Day (Fiji) |
| 51627 | May.05 | Event | 553 – The Second Council of Constantinople begins. |
| 51628 | May.05 | Event | 1215 – Rebel barons renounce their allegiance to King John of England — part of a chain of events leading to the signing of the Magna Carta. |
| 51629 | May.05 | Event | 1260 – Kublai Khan becomes ruler of the Mongol Empire. |
| 51630 | May.05 | Event | 1494 – Christopher Columbus lands on the island of Jamaica and claims it for Spain. |