Effrontery was founded by Péter Lipák (guitar, vocals), László Kovács (bass) and Zsolt Filák (drums) in 2001 in Martfű, Hungary. In order to progress musically, the then-developing group eventually added second guitarist Mihály Szilágyi and re-arranged their already existing material on dual guitars. Additional songs were being written afterwards and the band shortly began playing concerts as well.
In 2004, Gábor Nagy joined on vocals, and after the departure of László Kovács, he took over bass duties too.
In 2005, the first demo, "Flaming Mud" was recorded in Citysound Studio, Budapest. It was received with positive reviews in both the Hungarian and foreign press.
The next years were spent mainly with giving shows, and writing their first full-length album. Meanwhile, the band went through multiple line-up changes: Gábor Nagy quit, his successor on bass was Gábor Holics from 2006 till 2010. In 2010, Mihály Szilágyi left the band, and guitarist Gábor Czene and vocalist Zsolt Lédeczi was recruited. In the meantime, the music started to develop into a new direction. While still keeping their peculiar progressive death metal elements, additional classic wind and bowed string instruments were introduced, along with clean vocals, merging into the music and complementing it.
In December 2010, the debut LP's recording sessions started in Tonitrus Studio.
In 2011, Gábor Czene was replaced by Ferenc Sasvári, who also acted as the sound engineer in the post-production of the album. The disc, entitled "MayFly" has been released in dec., 2012.
In February 2013, the band’s first music video was shot for the song „The Effrontery”. In april, the group also participated in the finals of the Wacken Metal Battle Hungary competition, where they finished on the 5th place.
In summer, Effrontery appeared on two festivals as well, the Rockmaraton festival in June and the first MetalWar festival in early September. By the end of the year, Bence Rambács joined the band as bassist.