Sangharaja is the title given in many Theravada Buddhist countries to a senior monk who is the titular head either of a monastic fraternity (nikaya), or of the Sangha throughout the country. This term is often rendered in English as 'Patriarch' or 'Supreme Patriarch'.

Thotagamuwe Sri Rahula Thera was a Buddhist monk and an eminent scholar, who lived in the 15th century in Sri Lanka. He was a polyglot who was given the title "Shad Bhasha Parameshwara" due to his mastery in six oriental languages which prevailed in the Indian subcontinent. Sangharaja Thotagamuwe Sri Rahula Thera was also a distinguished author, veteran astrologer and a proficient ayurvedic physician.