Abseils

An abseil (/ˈæbseɪl/ or /ˈɑːpzaɪl/; from German abseilen, meaning 'to rope down'), also called a rappel after its French name, is a controlled descent of a vertical drop, such as a rock face, using a rope.

Climbers use this technique when a cliff or slope is too steep and/or dangerous to descend without protection. Many climbers use this technique to protect established anchors from damage. Rope access technicians also use this as a method to access difficult-to-reach areas from above for various industrial applications like maintenance, construction, inspection and welding. Rescue teams are also known for using this method as a way to access injured or stranded victims.

The origin of the abseil is attributed to Jean Charlet-Straton, a Chamonix guide who lived from 1840–1925. Charlet originally devised the technique of the abseil method of roping down during a failed solo attempt of Petit Dru in 1876. After many attempts, some of them solo, he managed to reach the summit of the Petit Dru in 1879 in the company of two other Chamonix guides, Prosper Payot and Frédéric Folliguet, whom he hired. During that ascent, Charlet perfected the abseil.

Early Dülfersitz or body rappel technique did not require a harness or any equipment

Latter double carabiner brake rappel technique used simple carabiner and sling as a harness

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Wikipedia