Old Spanish Trail movement organized to promote a paved automobile highway across the southern United States connecting 6 centers of historical interest: St Augustine, New Orleans, San Antonio, El Paso, Tucson and San Diego 

 December 11 & 12, 1915 Mobile, Alabama meeting to connect New Orleans to the east coast of Florida 

 Subsequent annual conferences held 1916 Pensacola, 1917 Tallahassee, 1919 Houston then San Antonio, 1921 Gulfport then Orange, 1922 New Orleans J

 July 1919 Houston, Texas conference held to ask San Antonio to lead movement across Texas - Harral Ayres chosen Managing Director; Gunter Hotel headquarters 

 November 1919 San Antonio conference gathered pledges for Texas - Councilors appointed every OST city and town to advise travelers of conditions and accommodations 

 June-December 1922 Mr. Ayres in Washington DC. gathering signatures of majority of senators and congressmen to declare OST a basic trunk line of US system assuring every mile of OST included in Federal Aid mileage - J. M. Wainwright of the U.S. War Dept declared highway an essential element of U.S. defense 

 August 1922 OST placed on General of the Armies, John J. Pershing's "Development of National Highways" map 

 1923 OST Beautification Committee organized to provide architectural drawings of highway and bridge signage, native stone county line markers, and business and residential stone gateways - Also provided guidance for tourist camp construction and maintainance 

 November 17, 1923 A message from President Coolidge read at dedication zero-mile stone of OST in San Diego, California 

 March 27, 1924 Texas Gov. Pat Neff dedicated zero-mile marker of OST on San Antonio City Hall grounds 

 April 2,3 &4, 1929 $16,000 gala dedication of zero-mile stone St. Augustine, Florida 

 1923 to 1931 Travelogs published annually as construction of highway and bridges progressed 

 April 1929 first motorcade San Diego to St. Augustine - October 1929 return motorcade St. Augustine to San Diego 

 April 29, 1930 Don Pablo de Ubarri, representative of His Majesty Alphonso XIII of Spain presented Royal Order of Spain, the Confederation of the Royal Order of Isabel la Catolica to Harral Ayres (cross to be returned to Spain upon Ayres' death) for his 10 years of leadership 

 Commemorative stone bench placed at corner Fredericksburg Road and Vance Jackson, San Antonio, Texas by the Alamo Mission Chapter of the Daughters of the Republic of Texas 

 2002 Plans begun for decade-long highly publicized OST Centennial Celebration with 2015 Mobile organizational reenactment, annual conference reenactments in various cities, 2023, 2024 and 2029 zero-mile marker reenactments and grand 2029 historic motorcade reenactments