It was rumored that Franz and Helmut Vonlichten were really pseudonyms for Ron and Jeff Pfeifer, but this was denied by the manager for E.S. Posthumus, and has since proven untrue.
On July 22, 2010, Helmut Vonlichten announced that that his brother Franz had died about two months before, in May of 2010. He stated that there were still one or two unreleased songs, but that the group was ceasing to be active. One of those unreleased songs ("Christmas Eve") was later released in November of 2010.
E.S. Posthumus was an independent music group that produced a form of 21st-century classical music that intertwined popular style drum rhythms with orchestral and electronic sounds. Their music is inspired by the Pythagorean philosophy which states that "music is the harmonization of opposites; the conciliation of warring elements". The E.S. is an acronym for "Experimental Sounds" while Posthumus (Latin: postumus, meaning "after" or "end") is a word that is meant to represent "all things past", suggesting the music was inspired by things that have ended, some time after they ended.
The group was formed in 2000 by brothers Helmut and Franz Vonlichten. Helmut and Franz studied piano with their mother. After graduating from high school, Franz worked in recording studios while Helmut attended and graduated from UCLA, with a degree in archaeology. Their music has been licensed by many movie and television production studios, being included in numerous movie trailers and television shows. E.S. Posthumus released three albums overall in their career.
On July 22, 2010, it was officially announced that Franz had died about two months before. After giving notice of his brother's death, Helmut stated that while there still may be one or two unreleased songs (one of them being their single "Christmas Eve" released in November 2010), the group would no longer be active. In November 2011, it was officially announced that Helmut Vonlichten had formed a new band called Les Friction, and released a preview of his new work with a track called "Torture".