Isthmia is a genitive noun with the meaning 'of the Isthmus.' It generally refers to the site that held the famous Isthmian Games near Corinth on the Isthmus. A natural assembly place for many Greeks and travellers. Isthmia in Antiquity was one of Greece's large Panhellenic sanctuaries and played host to the Isthmian Games (founded in 584 BCE) and hence held a special importance throughout the Greek and Roman periods, with its athletic and religious festivals coming second in significance only to Olympia.
This is a companion discussion topic for the original content at https://www.worldhistory.org/Isthmia/.