We may remark in passing that the retreat was often enlivened, or invaded, by friendly tourists from England, whose " frequent incursions " into Switzerland our recluse seems half to lament as an evil.
A fort was erected here in the 16th century to prevent the incursions of the free Cossacks and runaway serfs who gathered on the lower Volga, as also the raids of the Kalmucks and Circassians.
Several preliminary incursions had been already made, when in 1521 an opportunity presented itself for a more extended expedition.
The first of these canals, taken off on the right bank of the river a little below Hit, followed the extreme skirt of the alluvium the whole way to the Persian Gulf near Basra, and thus formed an outer barrier, strengthened at intervals with watch-towers and fortified posts, to protect the cultivated land of the Sawad against the incursions of the desert Arabs.
In order to prevent the incursions of '.ht Thracians, a wall was built across its isthmus, which was less than 5 m.