ed the Istrian coast towns, but
were defeated at Grado. The Emperor Basil occupied Dalmatia in 877 on
the pretext of Slav piracy. He gave the tribute from the Roman cities of
Dalmatia to the Croats and Narentans, so that Spalato, Zara, Trau, Arbe,
and the Byzantine cities of Veglia and Ossero had to pay tribute to the
Croats. The successful expedition of Pietro Orseolo II. against the
Narentan pirates tended to the greater security of the coast towns and
strengthened the bond which Venice was weaving.

In 933 a solemn treaty of peace was signed at Rialto between Istria and
Venice by the Marquis of Istria, the bishops of Pola and Cittanova, two
"locopositi," two "scabini," and twelve other trustees from Pola,
Capodistria, Muggia, and Pirano, there convened. A fresh treaty was made
in 977 with Capodistria, giving Venice special advantages, and these
negotiations were carried on without reference to the Imperial
authority, the nominal feudal lord. Walking thus warily, avoiding
offence to the Emperor of Germany, Venice took 200 years of continuous
political action to acquire the Istrian cities. By 1145 Venice had
obtained for herself liberty of commerce in most of the Istrian towns
and complete exemption from any kind of taxation; she had established at
Pola and Capodistria a representative, to look after the punctual
execution of treaties, and to protect Venetians from injustice, and had
also made the Istrian cities pay her a tribute, either in money or
products, obtaining also assistance for her navy from them whenever it
was fighting beyond Zara and Ancona. The importance attached by Venice
to these concessions is proved by the triumph which was given to the
squadron of Morosini and Gradonico when returning victorious from
Istrian waters. It was then that the doge assumed the title of "dux
totius Istriae," but the dates of the dedition of the several cities are
much later. The re-organisation of the communes took place between 1150
and 1180. The podesta had a council of assessors, the "consiglio
minore"; the larger "consiglio del popolo" was called together for the
more important matters, such as declaration of war, conclusion of peace,
legislation, imposition of taxes, election of podesta and consuls, &c.;
while many documents show that the whole body of citizens was summoned
to a "parlamento" for the publication of new laws, very important
deliberations requiring practical unanimity, the installation of fresh
magistrat