Referendums on sovereignty issues have been a relatively prominent feature of the international political and legal landscape since the late 18th century. In some cases comparatively peaceful reconfigurations of sovereignty among and within states have been achieved. In others the referendum device may have accompanied (or even caused) an escalation of conflict. Whilst at other times the people's constituent power has been deliberately avoided. This project seeks to investigate the role of the referendum where contested sovereignty is at stake. It focuses on two dimensions of contested sovereignty: Firstly, issues related to territorial concerns, such as secession; and secondly, functional issues, such as delegation to international/supranational organisations. The aim is to map dynamics across distinct geographical regions and over time to better understand the intersection between direct democracy and contested sovereignty in an age of increasing globalisation and territorial reconfiguration.