Well, I found out he wasn't a contemp of Isaiah, too many kings named Darius.
He was a contemp of Joshua - the high priest - and Haggai.
But his name means "Yahweh remembers" - what a good thing to know. God never forgets about us, even when it seems like we forget him. The Israelites were always forgetting what God did for them, but He always remembered them and provided for them - even when they were getting in trouble.