Born on 11 July 1864 in Hadarcha (Nikolaevka), Bulgaria, around 60 km from Varna. He was the third child of the priest Konstantin Deunovski and Dobra Georgieva. His grandfather on his mother’s side was Atanas Georgiev (1805–1865), an active public figure in the struggle for independence of the church during the Revival in the Bulgarian nation (18-19 century). His father, Constantin Deunovski (1830–1918) was the first Bulgarian teacher and priest in Varna.
In 1872 Peter Deunov was admitted to a primary school and he graduated from secondary school in Varna after the liberation of Bulgaria from the Ottoman Empire. On 24 June 1887 he completed his studies at the American School of Theology in Svishtov and was a teacher in Hotantsa, near Rousse, from the autumn of 1887 to the summer of 1888.
In August 1888 he left for the United States. He was enrolled at Drew Theological Methodist Seminary in Madison, New Jersey and completed his studies there in May 1892. During the autumn of 1892 he was enrolled at the Boston University School of Theology, defended a diploma thesis on “The Migration of the Germanic Tribes and Their Christianisation” and obtained his degree in June 1893. He was a regular student at the School of Medicine of the Boston University for a year.
In 1895 Deunov returned to Bulgaria, settled in Varna and refused the positions offered to him as Methodist and Theosophic preacher. In 1896 he published Science and Education, in which he analyzed the development of mankind in the dramatic world events, about the foundations of a new culture which he thought was bound to take place during the forthcoming century.
In 1896 he was one of the founders of the “P. R. Slaveikov” community and cultural centre. He was appointed a librarian and during the subsequent years he delivered the following lectures in Varna: “The Origin of Man”, ”Survey of Ancient and Modern Philosophy”, “Science and Philosophy”, “Why and How We Live” and “The Basis of Enlightenment”.
In 1897 Peter Deunov, together with some of his followers in Varna, founded a “Society for the Elevation of the Religious Spirit of the Bulgarian People”, with the following members: Dr. Georgi Mirkovich, Maria Kazakova, Todor Stoyanov, Penyu Kirov, Anastassia Jelyazkova and Milkon Partomyan. He published the brochure of mystic texts in the same year under the title of “Hio-Eli-Meli-Mesail”. The events from 1897 placed him at the centre of the spiritual society, which later on developed into a Synarchic Chain (1906) and into the Universal White Brotherhood (1918), while he himself was distinguished as individuality with the byname of Master. Actually after 1897 it is much more appropriate to refer to him as “Master”, rather than as “Peter Deunov”, although the byname of “Beinsa Douno” gained currency in literary publications only in the 1930s. The etymology of the name of “Beinsa Douno” has Sanskrit roots and translates as The One Who Brings in the Good through the Word. He signed with this nickname some papers in the police, to reduce the pressure on him, obviously shocking the police officers with the question: Who are you? Otherwise, the use of “Beinsa Douno” is irrelevant.
In 1898 he wrote and delivered the lecture, An Appeal to My People (Nation), before the “Mother” Charity Society in Varna. This lecture is an appeal to social and spiritual self-identification. During the following year he recorded “The Ten Testimonies of God and The Divine Promise”. From 1899 Master Peter Deunov convened Annual Meetings in Varna, which were originally called Meetings of the Synarchic Chain. From then onwards until 1942 the Universal White Fraternity held its Annual Meetings at various places every year in August: in Varna (1899–1909), in Veliko Tarnovo (1910–1925), in Sofia (1926–1941), in the Rila and Vitosha mountains.
From 1901 to 1912 he travelled to various places in Bulgaria, delivered lectures and did phrenologic investigations of selected individuals among the people. He started delivering his lectures in public. The historic, cosmic and metaphysical figure of Christ has a central place in his lectures. In 1912, in the village of Arbanassi (near Veliko Tarnovo) he worked on the Bible and prepared The Testament of the Colour Rays of Light, which came out in September during the same year. The title page had a motto: “I will always be a faithful slave to Lord Jesus Christ - the Son of God, 15 Aug 1912, Tarnovo.”
On 16 March 1914 he delivered his first Sunday talk, which was officially taken in shorthand with title Behold the Man, which laid the beginning of the Power and Life series. Master Peter Deunov postulated the main principles of his teaching, which he called The New Teaching of the Universal White Brotherhood. On 8 February 1917 in Sofia he started a series of special lectures for married women, which lasted until 30 June 1932. During 1917-1918, at the time of the First World War, the government of Vassil Radoslavov sent him on exile to Varna under the pretext that his teaching was weakening the spirit of the soldiers at the front. He lived in the London Hotel (currently the Moussala Hotel) and was in correspondence with his followers. After the end of the First World War in 1918 the number of his followers all over the country started to grow rapidly and they reached 40,000 people in the late 1930s.
On 24 February 1922 he opened an School in Sofia, which he called School of the Universal White Brotherhood. It consisted of two classes of students. The General Class opened with a lecture titled The Three Lives, and the Special (Youth) Class with The Two Paths. Lectures were delivered before the two classes every week for 22 years — until December 1944.
In 1927 Master Beinsa Douno established the settlement of Izgrev near Sofia (today a residential area of the city) where he gathered his audience, followers and disciples to have a centre where the school worked. He settled permanently in Izgrev, where he delivered the various series of his Word. From 19 August 1927 he delivered a series of lectures at the annual meeting of the Universal White Brotherhood, comprising into the cycle with title The Path of a Disciple.
During the period 1929-1932 Master Peter Deunov established contact with Jiddu Krishnamurti (in the town of Ommen, the Netherlands), who left the Theosophical Society at that time and dissolved the Order of the Star in the East.
In the summer of 1929 he took his followers and disciples camping near the Seven Rila Lakes for the first time. On 21 September 1930 he opened a new series of his teaching, called the Sunday Morning lectures, which lasted until April 1944. From 1934 he started working on the Paneurhythmy - a series of twenty-eight exercises consisting of melody, text and plastic movements. Later on he added the exercises The Sun Rays and Pentagram.
On 4 May 1936 he was attacked by an adherent of a political party, causing brain haemorrhage and partial paralysis. In spite of his health problem, on 14 July Master Beinsa Douno went out camping with followers of his near the Seven Rila Lakes and he had recovered completely by 12 August.
On 22 March 1939 he wrote a message to his disciples titled The Eternal Testament of Spirit.
In the early 1944 during the air raids in Sofia he organized the evacuation of Izgrev to Marchaevo (a village not far from Sofia) while he stayed at the home of one of his disciples. He returned to Izgrev on 19 October 1944. On 20 December 1944 he delivered his last lecture The Last Word to the General Class.
Peter Deunov died on 27 December 1944. His body was laid in Izgrev.