1. Exposition

What was the first year of Cyrus, king of Persia?

Ezra 1:1 (ESV)

1 In the first year of Cyrus king of Persia, that the word of the LORD by the mouth of Jeremiah might be fulfilled, the LORD stirred up the spirit of Cyrus king of Persia, so that he made a proclamation throughout all his kingdom and also put it in writing:

Cyrus became king of the Medes by conquest in 549 BC,1 and he overthrew the Babylonian king Nabonidus in 539 BC.2 Most likely the first year is a time after this conquest, probably in 538 BC.