Out of sight of land they used astral navigation. The got as far afield as the Canary Islands and Cornwall.
Astral navigation; an alphabet.
Their alphabet and astral navigation.
Trade, an alphabet and astral navigation.
Astral navigation, alphabetic writing.
An alphabet, astral navigation.
Their alphabet and astral navigation.
An alphabet; astral navigation.
their alphabet
Their alphabet and astral navigation.
Trade, astral navigation, fighting, inventing an alphabet.
They gave us alphabetic writing and astral navigation.
An alphabet to improve writing efficiency.