The article presents the main results of the investigations carried out from 2009 to 2016 on the Early Christian and Medieval site of Yereryuk, located in the Shirak province at the northwestern extremity of the Republic of Armenia, by the LA3M laboratory of medieval archaeology, from Aix-Marseille University, in cooperation with the Institute of Archaeology and Ethnography of the Academy of Sciences of Armenia, represented on the spot by the Regional Museum of Shirak. The survey concerned notably the Yereruyk basilica, its dating, architecture, carved decor, its place in early Christian Armenia, and its links with Syria, as well as the hypothesis of a pre-Christian stratum. A special attention was also paid to the memorial area south of the church, with remains of monuments once supporting cross-topped stelae. The excavations in this zone brought to light a cemetery, in which the examination of more than seventy graves yielded twenty-nine dates obtained by radiocarbon analysis of human bones. It allowed the exploration of the hitherto poorly studied area of funerary archaeology in medieval Armenia, providing a first picture of the evolution of a Christian cemetery from Late Classical period almost to the 20th century. Geomorphological and archaeological studies carried out on the remains of monuments located to the east of the basilica allowed to better understand the function of these constructions and to approach their dating. The presentation reviews the results achieved by the mission, the questions raised by its investigations, some answers that could be brought, as well as the enigmas that still remain to be elucidated.