Before the arrival of mountaineering in the 18th century, the profession of mountain guide consisted of taking those who required or requested, for diverse reasons (war, religion, migration, the transportation of provisions) to be taken over the mountain passes mainly in winter.
The evolution of the profession is, in no small part, down to the creation of the famous Compagnie des Guides de Chamonix Mont-Blanc in 1821.
This was followed by the creation of other guide companies in all the major valleys in the Alps.
Throughout the 19th and 20th centuries, the profession of mountain guide accompanied or initiated the development of alpinism, followed by the exploration of mountain ranges in distant countries in every corner of the globe.
In France, after 1945 and the creation of the national mountain guide diploma, the profession became nationally recognised thanks to the development of winter sports, which conferred it with a previously unknown dimension of respect and popularity.
Today, the profession is practised all year round and in all latitudes!

Wikipedia link: http://en.wikipedia.org/wiki/Mountain_guide