In many countries World Book Day is held on 23rd of April. This was established by UNESCO in 1995. The connection to the 23rd of April was first established by booksellers in Spain in 1923 as a way to honour the famous Spanish author Miguel de Cervantes who died on that day. The 23rd of April is also the anniversary of the birth and death of William Shakespeare.
In the United Kingdom, World Book Day is held annually on the first Thursday in March to avoid the established international 23rd of April date due to clashes with Easter school holidays, and the fact that it is also the National Saint's Day of England, St Georges Day.