St Joseph's feast day was adopted by the Franciscans in 1399 and was added to the list of Roman Catholic feast days in 1479. St Joseph's Day on March 19 became a compulsory Catholic feast day in 1621. Pope Pius XII introduced the Feast of St Joseph the Worker on May 1 to honor workers around the world in 1955.
The tradition of constructing and burning fallas arose at some stage in the Middle Ages. Carpenters burnt broken pieces of work and remnants of wood collected during the winter to celebrate the spring equinox. At some point, the fires were moved to St Joseph's Day as he is the patron saint of carpenters.
According to the bible, St Joseph was the Virgin Mary's spouse and played an important role in Jesus' upbringing. St Joseph is often portrayed with a carpenter's square or other wood working tools, the infant Jesus and a staff with lily blossoms.
Ninots and fallas are important symbols of Saint Joseph's Day in Valencia. Ninots are figures made of papier-mâché and cardboard. They are carefully constructed and usually life-sized or larger. A group of ninots based on a particular theme is assembled into a falla. A falla is a collection of ninots to make a scene depicting a story or situation. It is usually filled with firecrackers and fireworks.
The theme of a falla may be political or touch on controversial or taboo issues in Spanish society. There are similarities between the fallas and the floats paraded through the streets during the Rosenmontag celebrations in Germany.
Saint Joseph's Day is the Patronal Feast day for Poland as well as for Canada, persons named Joseph, Josephine, etc., for religious institutes, schools and parishes bearing his name, and for carpenters. It is also Father's Day in some Catholic countries, mainly Spain, Portugal, and Italy.