Greece - 1975 Constitution

Part III - Organization and Functions of the State
Title Article 37
Chapter 2 - Powers and Liability from the Acts of the President
Section II - The President of the Republic
Article

37

(2) The leader of the party having the absolute majority of seats in Parliament shall be appointed Prime Minister. If the party has no leader, or if the leader has not been elected to Parliament, or there is no party spokesman, the appointment shall be made after the election of the leader of the party’s parliamentary group, which must occur within five days of the Speaker’s communication to the President of the Republic about the number of seats possessed by each party in Parliament.
(3) If no party has the absolute majority, the President of the Republic shall give the leader of the party with a relative majority an exploratory mandate in order to ascertain the possibility of forming a Government enjoying the confidence of the Parliament.
(4) If this possibility cannot be ascertained, the President of the Republic shall give the exploratory mandate to the leader of the second largest party in Parliament, or appoint Prime Minister, according to his judgement and with the consent of the Council of Democracy, a member or non-member of Parliament, who shall be able to obtain a vote of confidence. To this person the President of the Republic might delegate the right to dismiss the Parliament and conduct elections.

Amendment Constitution: Article 37 (1986)
Categories - Parliamentary party (Procedural responsibilities)
Source own translation