Who is Tiberius from The Twelve Caesars and what is their importance?

Tiberius is not an honorable emperor. He shows no interest in politics, then, after Augustus dies, he steps up as his stepson wishes he would, and takes over. He does nothing spectacular and is rather lazy when it comes to ruling, even letting other provinces invade parts of the Roman Empire. He goes into seclusion so he can freely engage in his sexual vices. People believe Gaius gave him a slow acting poison to kill him.