It is possible that this unit was formed from another regiment, renamed in honour of the emperor Maximian ( AD286-305), who adopted the title ‘Herculius’ soon after his accession in 286. The only record of this units name is the Olenacum entry in the Notitia Dignitatum, which has been tentatively identified with Elslack (Olenacum) near Skipton in Yorkshire.
Evidence for the presence of Ala Primae Herculaea in Britain
- Elslack (Olenacum) (Elslack, North Yorkshire?; Notitia Dignitatum xl.55; c. 4th/5th C. AD).