How was the Empire of Advancia-Sizzletown formed?

(first dispatch by me from almost a year ago, accidentally deleted.)
The leaders of Sizzletown made a statement on 20th of November 2000 to join the Kingdom of United Advancia, which the leader agreed. On 1st December 2000, the Empire of Advancia-Sizzletown was formed, covering All of the continent of Sizzle, Advancia and most parts of the continent of Memeland.