How do I resurrect essential NPCs in Skyrim?

I was having some problems in Whiterun with the guard because I needed to pay a fine of over 3000 gold (a considerable quantity for someone that just started the game), so I decided to kill all the guards. The problem came when Commander Caius (an essential NPC) started to attack me, so I attacked him too.

As essential NPCs cannot die, I decided to used the console to set him to be mortal. After that I killed him.

Some of my friends told me that this Caius is an important character in the game, so I want to resurrect him. I still have his corpse, if it's needed.

Is there any console command that can be used to resurrect someone?

Thanks.

Just open up the console. Click on his corpse (you should see his ref id show up as a text string) and enter the command resurrect