The Feria de Abril, also known as the Feria de Sevilla, is Seville's biggest party week, allowing the city to cheer itself up after the sombre devotion of Semana Santa (Spain's version of Easter).
See also: 50 Things to Do in Seville
The Feria de Abril tends to take place two weeks after Easter. This means that occasionally the event will fall in May (hey, this isn't as crazy as Oktoberfest, which is always predominantly in September!).
Dates for the Feria de Abril aren't normally fixed until late in the previous year. For 2014, Seville's government met in October 2013 to choose a date, as Semana Santa 2014 falls quite late in the spring. They chose to main the two week gap.
Exact Dates for Feria de Abril 2014
So, Feria de Abril 2014 will take place from Tuesday May 6 to Sunday May 11, 2014.
Feria de Abril 2015
If the Seville government chooses to continue to separate Semana Santa and the Feria de Abril by two weeks, then the following event will take place from April 21 to April 26, 2015.