Max Mercury, also known as Max Crandall, was a scout for the U.S. in the early 1800s. When he discovered the plan to ambush the local Blackfoot clan, the shaman gave him super speed, so he could get there quickly, but died in the process. Max ran to the battle and disarmed both the Americans and the Indians, and was given the name Awehota ("Windrunner"). A few years later, he felt the need to faster than he had ever run before, being called in by the "speed force." However, he hesistated and was flung far into the future.

Over the years, he did this a number of times, until he finally landed in the present day, where he lives with his daughter Helen and trains Bart Allen, a speedster from the future who fights crime as "Impulse." Widely reguarded as the zen master of speed, speedsters often go to him for advice.


Sources
http://www.dccomics.com/features/theflash/bios/bio5.html
http://www.hyperborea.org/flash/max.html