[Sidenote: Protection of a water frontier.]

The margin of river, lake and sea has always attracted the first
settlements of man because it offered a ready food supply in its animal
life and an easy highway for communication. Moreover, a water front made
a comparatively safe frontier for the small, isolated communities which
constituted primitive societies. The motive of protection, dominant in
the savage when selecting sites for his villages, led him to place them
on the pear-shaped peninsula formed by a river loop, or on an island in
the stream or off the coast; or to sever his connection with the solid
land, whence attack might come, and provide himself with a boundary
waste of water by raising his hut on piles above the surface of lake,
river or sheltered seacoast, within easy reach of the shore. In this
location the occupant of the pile dwelling has found all his needs
answered--fishing grounds beneath and about his hut, fields a few
hundred feet away on shore, easily reached by his dug-out canoe, and a
place of retreat from a land enemy, whether man or wild beast.

[Sidenote: Ancient pile villages.]

Such pile dwellings, answering the primary need of protection, have had
wide distribution, especially in the Tropics, and persist into our own
times among retarded peoples living in small, isolated groups too weak
for effective defence. They were numerous in the lakes of Switzerland[580]
and northern Italy down to the first century of our era, and existed
later in slightly modified form in Ireland, Scotland, England and
southern Wales.[581] In ancient Ireland they were constructed on
artificial islands, raised in shallow spots of lakes or morasses by
means of fascines weighted down with gravel and clay, and moored to the
bottom by stakes driven through the mass. Such groups of dwellings were
called _Crannogs_; they existed in Ireland from the earliest historical
period and continued in use down to the time of Queen Elizabeth. In the
turbulent twelfth century, the warring lords of the soil adopted them as
places of refuge and residence.[582] Herodotus describes a pile village of
the ancient Thracians in Lake Prasias near the Hellespont, built quite
after the Swiss type, with trap doors in the floor for fishing or
throwing out refuse. Its inhabitants escaped conquest by the Persians
under King Darius, and avoided the fate of their fellow tribesmen on
land, who were subdued and removed as colonists to Asia.[583]

[Sid