The Aivathiuda (Rh. "Horse-people") were early ancestors of the Éothéod (and thus Rohirrim). Most of the tribes of the Aivathiuda – the Alciswardias or Alcisgairus, Berilas, Anthars, Gadrauhts, Aivadiurias, Marhungs, Paidareiks, Waluhandus and Waldandungs – later became the Éothrym.
Aivathiuda of renown
The MERP Mirkwood and Riders of Rohan source-books give the clans' names as Ailgarthas, Ailgras, Beorills, Anthars, Gadraughts, Eoadars, Mahrlings, Padaruiks, and Waildungs, a mix of modified Anglo-Saxon and Gothic forms.
The Inlandsea Module also mentions a tribe called "Waluslahandona" = Waluhandus
LOTRO uses the form "Ai thúda" a wrong or strangely anglicised spelling of Gothic Aivathiuda.
- MERP: Mirkwood
- MERP: Riders of Rohan