The pearl fisheries of Bavaria have been prominent since the sixteenth century. They exist principally in the districts of Upper Franconia (_Oberfranken_) and Upper Palatinate (_Oberpfalz_), the several tributaries of the Danube between Ratisbon and Passau, and in those tributaries of the Main and the Saale which rise in the Bavarian mountains, such as the Oelsnitz, the Lamnitz, Schwesnitz, Grünebach, Vils, and the Perlbach; also in the district of Lower Bavaria, where in nine districts alone there are one hundred pearl-bearing streams and lakes, of which the most important are the Regen, the Isar, and the Ilz.[211] Early in the sixteenth century, the river Ilz had the reputation of yielding the choicest pearls in Lower Bavaria. The right to them was reserved to the bishop of Passau, and a decree was made in 1579 that persons convicted of poaching on these reserves should be hanged.[212] Since that time there have been few decades in which the gems have not been found in the woodland brooks and mountain streams that flow through the ravines and past quaint, interesting castles of the wonderful Bavarian highlands. Most of the prominent families in this beautiful region have collections of native pearls, and there is still some trade in them in picturesque Passau, at the junction of the Danube, the Ilz and the Inn. Tavernier wrote about 1670: “As for the pearls of Scotland, and those which are found in the rivers of Bavaria, although necklaces are made of them which are worth up to 1000 _écus_ (£225) and beyond, they cannot enter into comparison with those of the East and West Indies.”[213]