The Greek astronomer Hipparchus first invented our system of apparent magnitude. He gave the brightest stars a magnitude of 1 and increased the numbers for dimmer stars. About 300 years later Ptolemy of Alexandria created an encyclopedia of stars based on Hipparchus' work. The Persian astronomer Al-Sufi took Ptolemy's work and gave Arabic names to the stars some 800 years later. Medieval European astronomers simply translated Al-Sufi's work into Latin which is why many stars today have Arabic names.