"Alegrías" is a festive flamenco style that belongs to "cantiñas" group (cantes de Cádiz).
Its copla or stanza is usually composed by four octosyllabic verses. This is also called "alegría" stanza. Its melody is festive and incites to dance it. Its rhythm is influenced by "soleá" metric but in a more quickly way.
It seems that this style comes from Navarre-Aragon "jota" and was established in Cádiz in french occupation and "Cortes de Cádiz" time. That's the reason why its classic lyrics refers to Ebro river, "Virgen del Pilar" and Navarre.
It is widely believed that Enrique Buitrón was the one who set the current flamenco style of “alegrías” and Ignacio Espeleta who introduced the characteristic "tiriti, tran, tran ...” This “palo” has been interpreted by well-known artists: Enrique Mellizo, "Pinini" Pericón de Cadiz, La Perla de Cadiz, Chato de la Isla, Aurelio Selles, "El Folli" and Chano Lobato.