English: In 1377, he had himself crowned king of Bosnia and of Serbia, claiming to be the heir of Serbia's extinct Nemanjić dynasty. As the Kingdom of Bosnia continued to expand, Tvrtko's attention shifted to the Adriatic coast. He gained control of the entire Pomorje and the major maritime cities of the area, established new settlements and started building a navy, but never succeeded in subjugating the lords of the independent Serbian territories. The death of King Louis and the accession of Queen Mary in 1382 allowed Tvrtko to take advantage of the ensuing succession crisis in Hungary and Croatia. After bitter fighting, from 1385 to 1390, Tvrtko succeeded in conquering large parts of Slavonia, Dalmatia, and Croatia proper.