substantial dwellings in the place.  Here at the end of August is held a great annual fair, which is attended by traders from India, Kashmir, Mongolia, Chinese Turkestan, China proper, and Lhassa; but by November the place is deserted.  The traders disperse, and the few residents of Gartok, together with the viceroys, retire down the Indus Valley to the more sheltered village of Gargunza (14,140 feet or 4311 meters elevation), which represents the limits of permanent settlement in these altitudes.[1243] The Sutlej Valley route from the Punjab to Lhassa is capped near its summit at an altitude of about 5000 meters by the summer market, of Gyanema, whose numerous types of tents indicate the various homes of the traders from Lhassa to India.[1244]

[Sidenote:  Pass peoples.]

Natural thoroughfares, whether river highways or mountain pass routes, draw to themselves migration, travel, trade and war.  They therefore early assume historical importance.  Hence we find that peoples controlling transmontane routes have always been able to exert an historical influence out of proportion to their size and strength; and that in consequence they early become an object of conquest to the people of the lowlands, as soon as these desire to control such transit routes.  The power of these pass tribes is often due to the trade which they command and which compensates them for the unproductive character of their country.  In the eastern Himalayas the Tomos of the Chumbi Valley are intermediaries of trade between Darjeeling and Tibet, In the western Himalayas, the Kumaon borderland of northern India, which commands some of the best passes, has made its native folk or Bhutias bold merchants who jealously monopolize the trade over the passes to the Tibetan markets.  They stretch for a zone of thirty miles south of the boundary from Nepal to Garhwal along the approach to every pass, each sub-group having its particular trade route.[1245]

[Sidenote:  Transit duties.]

It is always possible for such pass tribes to levy a toll or transit duty on merchandise, or in lieu of this to rob.  Caesar made war upon the Veragri and Seduni, who commanded the northern end of the Great St. Bernard Pass, in order to open up the road over the Alps, which was traversed by Roman merchants magno cum periculo magnisque cum portoriis.[1246] The Salassi, who inhabited the upper Dora Baltea Valley and hence controlled the Little St. Bernard wagon road leading over to Lugdunum or Lyons, regularly plundered or taxed all who attempted to cross their mountains.  On one occasion they levied a toll of a drachm per man on a Roman army, and on another plundered the treasure of Caesar himself.  After a protracted struggle they were crushed by Augustus, who founded Aosta and garrisoned it with a body of Praetorian cohorts to police the highway.[1247] The Iapodes in the Julian Alps controlled the Mount Ocra or Peartree Pass, which carried the Roman wagon road from Aquileia over the mountains down to the valley of the Laibach and the Save.  This strategic position they exploited to the utmost, till Augustus brought them to subjection as a preliminary to Roman expansion on the Danube.[1248]