 In all cases, the field studies relationships between "political entities" (polities) such as sovereign states, inter-governmental organizations (IGOs), international non-governmental organizations (INGOs), other non-governmental organizations (NGOs), and multinational corporations (MNCs), and the wider world-systems produced by this interaction.International relations is an academic and a public policy field, and so can be positive and normative, because it analyses and formulates the foreign policy of a given state.As political activity, international relations dates from the time of the Greek historian Thucydides (), and, in the early 20th century, became a discrete academic field (no.