I understand that there is a general Jewish tradition that the Western Wall/Kotel was built by the poor (I believe under the command of King Solomon) [(link)][1]. What is the source for the tradition (being built by the poor, but also when it was built)? All archeology has uncovered is that it was built after the year 20 CE [(link)][2].


  [1]: http://www.aish.com/w/a/46804772.html
  [2]: http://www.nbcnews.com/id/45419597/ns/technology_and_science-science/t/coin-discovery-sheds-new-light-sacred-jerusalem-site/