The Arabs, who voyaged to Ceylon and Java, appear to have learnt its use from the Chinese, and it is probably from them that the mariners of Barcelona first introduced its use into Europe.
The first mention of it is given in a treatise on Natural History by Alexander Neckam, foster-brother of Richard, Coeur de Lion.
Another reference, in a satirical poem of the troubadour, Guyot of Provence (1190), states that mariners can steer to the north star without seeing it, by following the direction of a needle floating in a straw in a basin of water, after it had been touched by a magnet.

But little use, however, seems to have been made of this, for Brunetto Latini, Dante's tutor, when on a visit to Roger Bacon in 1258, states that the friar had shown him the magnet and its properties, but adds that, however useful the discovery, "no master mariner would dare to use it, lest he should be thought to be a magician." Indeed, in the form in which it was first used it would be of little practical utility, and it was not till the method was found of balancing it on a pivot and fixing it on a card, as at present used, that it became a necessary part of a sailor's outfit.

This practical improvement is attributed to one Flavio Gioja, of Amalfi, in the beginning of the fourteenth century.
[Illustration: THE MEDITERRANEAN COAST IN THE PORTULANI.] When once the mariner's compass had come into general use, and its indications observed by master mariners in their voyages, a much more practical method was at hand for determining the relative positions of the different lands.

Hitherto geographers (_i.e._, mainly the Greeks and Arabs) had had to depend for fixing relative positions on the vague statements in the itineraries of merchants and soldiers; but now, with the aid of the compass, it was not difficult to determine the relative position of one point to another, while all the windings of a road could be fixed down on paper without much difficulty.

Consequently, while the learned monks were content with the mixture of myth and fable which we have seen to have formed the basis of their maps of the world, the seamen of the Mediterranean were gradually building up charts of that sea and the neighbouring lands which varied but little from the true position.