Father Roberto Landell de Moura (January 21, 1861 – June 30, 1928), commonly known as Roberto Landell, was a Brazilian Roman Catholic priest and inventor. He is best known for his work developing long-distance audio transmissions, using a variety of technologies, including an improved megaphone device, photophone (using light beams) and radio signals. It was reported in June 1899 that he had successfully transmitted audio over a distance of 7 kilometers (4.3 miles), which was followed by a second, public, demonstration on June 3, 1900. A lack of technical details makes it uncertain which sending technology was being used, however, if radio signals were employed, then these would be the earliest reported audio transmissions by radio. Landell received patents in Brazil and the United States during the first decade of the 1900s. He had many technical and financial difficulties to develop his research, he worked most of the time alone and found a lot of resistance and disbelief on the part of authorities and the population, which prevented his recognition in life from being broader, but in certain spheres his stature scientific research was duly appreciated and it is known that he rejected opportunities to publicize its inventions. Thus, the popular idea that was formed around him as a persecuted, wronged and suffered scientist facing an insensitive and obscurantist world, is a partial truth. His biography still has many gaps and only part of his scientific legacy has been studied, with a lot of autograph documentation still to be explored. In any case, in Brazil he has already received a series of official honors and recognitions. He is honorary citizen of city of São Paulo, patron of Science, Technology and Innovation in the municipality of Porto Alegre, patron of Brazilian radio amateurs, and in 2012, by presidential decree, his name was inscribed in the Tancredo Neves Pantheon of the Fatherland and Freedom . Early life Robert Landell de Moura was born in Porto Alegre, Brazil in 1862. His father was Ignacio de Moura, and he had five brothers: João, Edmundo and Ricardo (all apothecaries), Dr. Ignacio Landell, a physician, and Pedro Landell de Moura, a São Paulo merchant. He was ordained to the Catholic priesthood in 1886 in Rome, and also conducted studies in the physical sciences. Experimental work Landell began experiments in wireless communication in Campinas and São Paulo in the period 1893–1894. A biographical review recounted that he