I did some surfing on the web tonight and I came across this website that had the following information on the soup known as Pho:
If you can imagine beef noodle soup for breakfast, then you decidedly want to try Pho, a Vietnamese dish that has been around for nearly 100 years.
. . . Pho (pronounced "phir" in English) is influenced by the Chinese and French cuisines, and was believed to have originally derived from a French soup, "pot au feu" (pot on fire), which Wikipedia defines as a French beef stew. This is usually a mixture of cuts of beef, vegetable, and spice.
Pho had its humble beginnings nearly 100 years ago, and at that time was basically boiled beef, broth and noodles. It has since evolved into much more than that. During the war in Viet Nam, when beef became scarce, a pork version (pho lon) evolved.
The web page also includes a recipe for Pho.