Siam was a gift from David B. Sickles, the American consulate in Bangkok to First Lady Lucy Hayes, wife of president Rutherford B. Hayes. In 1878 Siam was transported to the US in the hull of a ship into port, then via Wells Fargo to the White House. History reveals that she was allowed to roam the White House at will and often made appearances when during presidential functions. Read the entire story at the Rutherford B. Hayes Presidential Center site.
Thanks to Kizzee for the photo posted on Flickr. We seached the internet and could not find a picture of Siam.