103. The fleet of Drusus had failed in their attempt to
pass, or even to approach, the Sound (styled, from an
obvious resemblance, the Columns of Hercules), and the naval
enterprise was never resumed (Tacit. de Moribus German, c.
34). The knowledge which the Romans acquired of the naval
powers of the Baltic (c. 44, 45) was obtained by their land
journeys in search of amber.