Icelus Martianus (died 69 CE) was a freedman of and adviser to the Roman Emperor Galba.
[3] Icelus was given the name Martianus and elevated to the rank of knight by Galba.
This was contrary to the Tiberian law which stipulated that no freedman could be elevated to equestrian rank without first having three previous generations of free birth.
Icelus rivalled Titus Vinius, and Cornelius Laco for influence over Galba who executed numerous Roman citizens without trial.
[4] Icelus along with Laco opposed the adoption of Otho by Galba.