Silla began as one of the six ruling clans of Saro. Around 80 AD, the leadership of Saro was seized and consolidated by Talhae of Silla. The state of Saro began forming a confederation with neighboring walled-town states, and gradually gained strength. Saro ultimately became the Kingdom of Silla.
It was not until 94 AD that Gaya initiated hostilities against Silla. Subsequently, the two powers went to war again in 97 AD. Both of these campaigns were unsuccessful.
In the twenty-third year of the reign of Pasa Isageum, Silla gained control over the previously independent states of Siljikgok (present-day Samcheok), Eumjipbeol (present-day northern Gyeongju), and Apdok (present-day Gyeongsan). Six years later, Silla took over the states of Biji (present-day Hapcheon), Dabeol (present-day Pohang), and Chopal (present-day Changwon) as well. These, together with U-si and Kueo-ch’il, which has been added the year before Pasa's accession, constituted a considerable increase in the territory of the Kingdom of Silla.