Theodoret of Cyrus, on Jer 1:2

“The word of the Lord which came to him in the days of Josias the son of Amon king of Juda, in the thirteenth year of his reign.”

“King Josiah's father was Amon, an impious man. His grandfather was Manasseh, who had instructed Josiah's father in his impiety. Josiah, on the contrary, went the exact opposite of them, siding with the party of the godly. His children, however, showed no interest in their father's virtue and imitated their forefathers' godlessness. Knowing this in advance, therefore, the God of all elected the prophet in the thirteenth year of Josiah's reign and commanded him to foretell the calamities that would befall both city and people.”

Imported from an open dataset — not yet checked against the printed edition.