While balancing on webbing is a relatively new invention, rope walking has been around since at least the Roman times. More on tightrope, highwire and slackline
Slackline-Tools - history
Walkin' a Tightrope - Sports Illustrated
Slackline History, Slackline Essentials
Why is slacklining similar to slack rope walking and tightrope
Slacklining history, from tightrope and highwire to slackline
The History of Slacklining - A Brief Look At How We Got Here
Explore the YogaSlackers Practices: Slack, Acro, Handstands and More
Slacklining history, from tightrope and highwire to slackline
Slackliner walks above active volcano and clouds to break two
Meet the crew pushing the obscure extreme sport of free solo