Russel was the cloaked figure to whom the werewolf brought Eric's father's crown, who then told Eric "Don't be a hero, Viking" and walked away. That puts Russel at around 1000 yrs old already to have met a pre-turned Eric.

So, whoever said Godric was the oldest was either misinformed or Russel kept his true age a secret.

An interview with the actor playing Russel reveals that Russel was an ancient sun-worshiping Celt hailing from the Carpathian Mts. While the actor was given permission to make up that background story, the age was real.