Ordo Equitum Solis (abbreviated OES) are an alternative music band consisting of French Leithana, pseudonym of Nathalie Herrera (vocals, keyboards, zither, percussions) and Italian Deraclamo, pseudonym of Paolo De Marco (vocals, guitar). The duo formed in 1988, and released albums and toured between 1990 and 2000. In 2001 the band suddenly broke up, but there was a reunion in 2010.The musical style of OES does not fall into a precise category.