Kings named Rama have ruled, for 10 points, what country formerly known as Siam?
One of this country's many embassies to a European nation was depicted in a Jean-Leon Gerome painting. This country's government transitioned to a constitutional monarchy during the Promoter's Revolution. After its soldiers killed Inspector Grosgurin, this country tangled with a colonial power in the Paknam incident. Taksin was the only king of its Thonburi dynasty. Although it often warred with France, this country was the only Southeast Asian state to avoid colonization by Europeans. This country's king Mongkut, a member of its Chakri dynasty, allowed Anna Leonowens to educate his children. Kings named Rama have ruled, for 10 points, what country formerly known as Siam? 
One of this country's many embassies to a European nation was depicted in a Jean-Leon Gerome painting.
Thailand [or Siam until mentioned] 