protect the soft sandstone rock. These include that only natural holds of the rock are allowed for climbing. These rules for free climbing are still in use and haven't changed significantly. 1914 : Siegfried Herford and companions, climb, using shoulder stands, the Flake Pitch on the Central Buttress of Scafell (5.8 A0, 5.9 today), Britain's hardest climb at the time (3-pitches). 1916 : Ivar Berg free soloed the 60-foot Cave Arête Indirect at Laddow Rocks, Derbyshire, England, at E1 5a (5.9+), it was the first E1. 1918 : climbs, unprotected, Westkante at the Wilder Kopf, in the Saxon Switzerland climbing region, at Sax VIIIa, the world's first-ever , (2-pitches). 1920s 1920s–1930s : Robert L. M. Underhill and Miriam Underhill (Miriam E. O'Brien), Early climbing couples; Robert introduced European climbing techniques in an article in the 1931 Bulletin of the Sierra Club. 1921 : Oswald Kunis leads the unprotected Kuniskante on Rauschentorwächter, in the Saxon Switzerland climbing region. Sax VIIIa/VIIIb, the world's first-ever . 1921 : and Gustav Haber climb the 1,000-foot Ha-He Dihedral UIAA VI+ (5.9+) at , in Austria, in 2 days of climbing; would not be repeated until the 1950s. 1922 : Hans Rost leads, with 2 protection rings, the run-out on Rostkante, on Hauptwiesenstein, in the Saxon Switzerland climbing region. Sax VIIIb, the world's first-ever . 1922 : and party ascend the unprotected Illmerweg on Falkenstein, Sax VIIc or , in the Saxon Switzerland climbing region; famous overhang known as "the mailbox". 1923 : , adding to Dülfer's five grades, creates the Roman Numeral European rating system for rock climbs (Grades I to VI); this system eventually became UIAA grading. 1924 : Felix Simon and Roland Rossi climb the 850-metre North Face of Monte Pelmo, in the Dolomites, Italy, at UIAA V+, placing 11 pitons. 1925 : July 28, Fritz Wiessner, Roland Rossi climb Southeast Face of Fleischbank, Austria, at VI+/5.10a, 11-pitches with 4 free pitches at Grade VI, a tension traverse pitch, and an aid pitch over a roof. 1925 : August 1, and Fritz Wiessner climb the 750-metre North Face of Furchetta, Dolomites, a 20-pitch route and two pitches of UIAA VI (5.9) near the top. 1925 : August 7, Gustav Lettenbauer and climb the 1,200-metre NW Face of Civetta, Dolomites in a day, UIAA VI- (5.9), 44-pitches, 15 pitons; world's hardest big wall climb. 1925 : Albert Ellingwood and a party of three climb