Bithynia was an ancient region and Roman province located on the south-eastern edge of the Marmara Sea in the north-western part of present-day Turkey. It was bordered by Mysia, Paphlagonia, and Phrygia. From the fourth century B.C., it was an independent Hellenistic kingdom, and around 74 B.C. it became a Roman province. During the seventh century A.D. it was incorporated into the Byzantine theme of Opsikion. It became a border region to the Seljuk Empire in the 13th century and was eventually conquered by the Ottoman Empire in the early 14th century. Several major cities of Bithynia sat on the fertile shores of the Propontis or in the forested inland, such as Nicomedia (İzmit-Kocaeli), Nicaea (İznik), Chalcedon (Kadıköy), Cius (Gemlik), Prusa ad Olympum (Bursa) and Apamea Myrlea (Mudanya). Besides being a coastal region, it is also occupied by mountains as well as forests and has valleys of great fertility. Since the studies of F.K. Dörner in the 1950s, archaeologically and historically Bithynia became a special focus in the fields of ancient Anatolian studies. The aim of this online video conference is to report on the state of research concerning Bithynia during the Greek, Roman, and Byzantine periods between ca. early sixth century B.C. and early 14th century A.D.