Ekathosarot succeeds his brother Naresuan, who has died during his campaigns to subjugate the Shans in 1605.

Coincident with Ekathosarot’s accession, the Ayutthaya kingdom has reached the maximum extent.

However, immediately after the coronation, the Burmese principality of Lanna, an Ayuttayan tributary for the past several years, breaks away from Siamese control.