At some point before the events depicted in the Babylon 5 series, Mollari I was the leader of the Centauri Republic. He had, in the words of Londo Mollari, "ended badly." Nothing else has yet been revealed about Mollari I beyond the fact that he existed and was Emperor.
In 2262, Londo Mollari became the second member of his family to be named Emperor when he was named Emperor Mollari II.
Mollari's character becomes more detailed and rounded as the series progresses, and he is shown to be both likable, and capable of acts of kindness and generosity, even forming something of a grudging friendship with G'Kar.
EmperorMollari II Following the galactic war with the Shadows, Mollari eventually rises to Emperor of the Centauri Republic, and becomes EmperorMollari II as another member of his family had been named Emperor.
Mollari was told to execute Sheridan, and he was able to convince his Keeper that he was soon going to kill both Sheridan and Delenn.