What is "surasena"

Surasena (or Sourasena) (, ) was an ancient Indian region corresponding to the present-day Braj region in Uttar Pradesh. According to the Buddhist text Anguttara Nikaya, it is mentioned in the Ramayana as an earlier Janapada state from at least 1000 BCE. Surasena was one of the solasa (sixteen) Mahajanapadas (powerful realms) in the 7th century BCE. The ancient Greek writers refer to the region as Sourasenoi and mention its capital as Methora.