That was Grima Wormtongue if you are talking about the trailer.....
It was a nice looking blond guy...I thought it was Faramir, but maybe it was just one of his guard. It looked like they were getting his armor on him. It definitely was not Denethor, though...I looked at the quintessential page.
Ahhh...I found the poem. Aragorn says it in the book. It's about Eorl the Young, so it's certainly Theoden.