LL , I've written NINE lines on the subject in my last "lengthy " post (not 2 pages)! When next we meet at Cathedral, I'm perfectly to discuss rope history with you , en français, si tu préfères; until that time, I'll just point out one difference between hemp ropes and static ones of a thickness appropriate for climbing-- the original historical premise for the adage "the leader must not fall" was that the HEMP ROPE would break under a shock load (see Whymper and the history of the 1st ascent of the Matterhorn) and was therefore only really good for helping a less skilled person than the leader; a modern STATIC ROPE of a thickness appropriate for climbing will BREAK the climbers BODY or SCRAMBLE internal organs in a dynamic fall; the modern concern with static materials to tie in to a belay has come about from studying some accidents where someone clipped into an anchor, climbed above it to place another piece, fell off, and either the sling broke, or a carabiner broke, causing a much longer and injurious fall ( in at least one case, fatal). During the 22 years that I was the AAC delegate to the UIAA Safety Commission (Commission de Sécurité), we studied several such cases, lab tests were done, and the reasons for the failure of the gear was determined. In the last few years, Black Diamond, Petzl and especially DMM have, in their testing labs, continued to make such tests and have made available very informative videos to help climbers and alpinists , "noobs" and mountain professionals alike, to understand the strengths and limitations of the various materials. This is helpful; continuing to "blame the bolts" and sport climbing for the lack of understanding of the forces and risks involved in climbing is not. I've now added 19 lines of text to my total contribution to this site--YOU STILL WIN-- but as 70 year old, active climber (& guide) who started climbing in 1964, who has read everything I could lay my hands on about climbing technique, safety, materials, and history since, and who volunteered my time for 22 years as the AAC delegate on the UIAA Safety Commission, I don't need you to quote me Robert Underhill's reference from Freedom of the Hills any more than I need an introduction to the Holy Bible from an annoying door to door Christian evangelist!