“So lasting they are, the rivers!” Only think. Sources somewhere in the mountains pulsate and springs seep from a rock, join in a stream, in the current of a river, and the river flows through centuries, millennia. Tribes, nations pass, and the river is still there, and yet it is not, for water does not stay the same, only the place and the name persist, as a metaphor for a permanent form and changing matter. The same rivers flowed in Europe when none of today’s countries existed and no languages known to us were spoken. It is in the names of rivers that traces of lost tribes survive.