ical domains. Their limited area, which enabled them to
be compassed, enabled them also to be appropriated, controlled and
policed. The Greek excluded the Phoenician from the Aegean and made it
an Hellenic sea. Carthage and Tarentum tried to draw the dead line for
Roman merchantmen at the Lacinian Cape, the doorway into the Ionian
Sea, and thereby involved themselves in the famous Punic Wars. The whole
Mediterranean became a Roman sea, the _mare nostrum_. Pompey's fleet was
able to police it effectively and to exterminate the pirates in a few
months, as Cicero tells us in his oration for the Manilian Law. Venice,
by the conquest of the Dalmatian pirates in 991 prepared to make herself
_dominatrix Adriatici maris_, as she was later called. By the thirteenth
century she had secured full command of the sea, spoke of it as "the
Gulf," in her desire to stamp it as a _mare clausum_, maintained in it a
powerful patrol fleet under a _Capitan in Golfo_, whose duty it was to
police the sea for pirates and to seize all ships laden with contraband
goods. She claimed and enforced the right of search of foreign vessels,
and compelled them to discharge two-thirds of their cargo at Venice,
which thus became the clearing house of the whole Adriatic. She even
appealed to the Pope for confirmation of her dominion over the sea.[576]
Sweden and Denmark strove for a _dominum maris Baltici_; but the Hanse
Towns of northern Germany secured the maritime supremacy in the basin,
kept a toll-gate at its entrance, and levied toll or excluded merchant
ships at their pleasure, a right which after the fall of the Hanseatic
power was assumed by Denmark and maintained till 1857. "The Narrow Seas"
over which England claimed sovereignty from 1299 to 1805, and on which
she exacted a salute from every foreign vessel, included the North Sea
as far as Stadland Cape in Norway, the English Channel, and the Bay of
Biscay down to Cape Finisterre in northern Spain.[577]

At the beginning of the sixteenth century the Indian Ocean was a
Portuguese sea. Spain was trying to monopolize the Caribbean and even
the Pacific Ocean. But the immense areas of these pelagic fields of
enterprise, and the rapid intrusion into them of other colonial powers
soon rendered obsolete in practice the principle of the _mare clausum_,
and introduced that of the _mare liberum_. The political theory of the
freedom of the seas seems to have needed vigorous support even toward
the end of the s