Herman Dalmatin was born at the beginning of the 12th century in Istria. He traveled in the Middle East and developed a wide knowledge of Arabic astronomy and mathematics. His most important work is De Essentiis, which he wrote in Bezier in 1143. In it he described his understanding of philosophy and science in light of European and Arabic thought. He left a significant mark on the development of western science and initiated the development of different scientific disciplines. The stamp was issued in 1993 for the 850th anniversary of the publication of De Essentius.