Ice axe history question

Does anyone know who started using two ice axes in stead of one?

Look into Chouinard’s “Climbing Ice” as well as “Yankee Rock and Ice.” Might have the info/history you seek 

Sockeye Scully wrote:

Look into Chouinard’s “Climbing Ice” as well as “Yankee Rock and Ice.” Might have the info/history you seek 

Ok I will thank you!

I took a look at my copy of "The Art of Ice Climbing", a modern and rather extensive Euro-centric book about ice climbing, to see what it had to say. It's a pretty cool book! A couple sections of interest:

"In the early days of alpinism, guides carried an alpenstock for balance on steep terrain and a small axe in their belt which they used to cut steps in the ice. In 1840, these two tools were combined to give the first ice axe."

"In 1962 Walter Bonatti and his companion Zapelli climbed the north face of the Grand Piller d'Angle which represented a new level of difficulty in ice climbing. The equipment they employed was still rudimentary, although in addition to their single ice ax they carried an "ice dagger" in their other hand, which gave them slightly more reassurance."

"In 1969, Reinhold Messner, a young Tyrolean alpinist, soloed the Davaille route on the north face of the Droites in just 9 hours. He was, apparently, back in Chamonix in time for lunch! That same year on Hell's Lum crag in Scotland, Cunningham made the first ascent of "The Chancer", a plumb vertical icefall which he climbed without cutting a single step. Frontpointing had finally come of age. Equipped with only two ice daggers, these pioneers demonstrated an extraordinary degree of mental and physical commitment. However they still lacked the tool that would give them as much confidence in their arms as they had in their feet. As early as 1964, Hamish MacInnes had started experimenting with a very short metal-shafted ice axe equipped with a steeply inclined pick that would become known as the "terrordactyl" (because climbers smashed their knuckles each time they swung the axe; terror-dactyl!'). This tool was ideal for the relatively soft snow-ice that was encountered in Scotland, and also for hooking on steep mixed terrain. It would soon be adopted by climbers all over the world.

[...some paragraphs about climbing development in the usa I'm not going to transcribe...]

"These [American] climbers [Chouniard and friends] were very inventive and started innovating with new tools and techniques. In 1970 they visited Scotland, bringing with them a new model of ice axe which had a short shaft and a steeply curved pick. They also designed a new crampon made from lightweight chrome molybdenum steel. The new equipment allowed them to push the level of difficulty in Scottish climbing - notably with the first ascent of the direct finish to Raven's Gully" in Glen Coe - but it was their meeting with Hamish MacInnes which proved to be the real catalyst for change. The new tools that emerged from their exchange of ideas gave climbers a new-found security on steep ice. 

"French alpinists were also working on new ideas, trying to improve on the ice dagger and traditional ice axe which were their preferred tools. Walter Cecchinel was the leading figure of the day.... etc... etc... By fine tuning his technique and using his axe in conjunction with an ice hammer, Cecchinel set about re-inventing ice climbing. The following winter [1972] he went on to make the second ascent of the 'Lagarde-Segogne' couloir on the Augille du Plan in fine style. This was perhaps the first ever example of "piolet traction" (pulling up on the shaft of the ice axe). When he became an instructor at ENSA, Cecchinel introduced this technique and presided a commision that codified how it should be taught. This institutional recognition contributed to the acceptance of "piolet traction" in France, as did an iconic Simond advertising poster which portrayed Cecchinel in action on steep ice.

"

The use of these new ice tools, whether Scottish, American or French, spread quickly around the world.... New terrain, such as steeper guillies and even frozen waterfalls, was opening up to climbers. In the same way that crampons had revolutionzed climbing at the beginning of the century, and the addition of front points had done the same in the thirties, these modern ice axes changed the way alpinists envisaged ascents of big ice and mixed routes. Ice became an asset rather than an obstacle, allowing climbers to move faster in relative safety."

***

Hope that is useful! While looking for the Simond poster on Google I came across this page, which actually discusses some of this same history (in Spanish). It is worth reading as well: https://guiasdelpicu.blogspot.com/2017/05/

EDIT: I just realized you are located in Belgium... the book was originally written in French, under the title "Glaces - arts, expériences et techniques". It is a bit hard to find in English but probably much more widely available in French.

Parallel evolution of the Chouinard tools with that of the all metal Terrodactyl tools designed by Hamish Macinnes. I think the Dru Couloir was the first application of Piolet traction in the Mont Blanc Massif.