Tango in general has a long and complicated history starting in the 1880s in Argentina. However, the development of Social (American) Tango is a fairly recent phenomenon. Entertainers in both the United States and in Europe began to take portions of Argentine Tango and mold them to fit their needs in the early 1900's.
The main purpose of the Ballroom Tango branching off from its Argentinian mother was to make it more standardized for competition. With more standardized steps, judges could better score the dance. One of the pivotal people in the creation and establishment of American Tango is Arthur Murray. He is largely responsible for the standardization of Tango in America through his dance schools.
Today, American or Ballroom Tango is significantly different than Argentinian Tango. Most can identify American tango steps by the acronym of the word itself, with each letter representing a specific movement within the 5-step basic. The “T” and “A” are the first two slow steps done by the couple. The remaining “N’, “G” and “O” are the steps that when combined are known as the “tango close”. American Tango is danced to 4/4 time signature with a recommended speed of 120 – 132 bpm.