The Third Biennial Conference of the Medieval Central Europe Research Network (MECERN) on the theme Between Three Seas: Borders, Migrations, Connections took place at the Faculty of Humanities and Social Sciences, Zagreb (Croatia), between 12 and 14 April 2018. Already an established scholarly forum, founded at a conference at CEU in 2014, MECERN’s third major international event attracted almost 100 participants from 15 countries in Europe and North America.