When the ancients gazed upon the celestial dome they noted the stars seemed to form patterns. These patterns were made by connecting the brighter stars with imaginary lines and stories were made and names given that reflected the local stories, myths and religious practices. Each age has seen what it wanted to see.
For thousands of years this was the the calendar that marked the seasons. The Sun and the Moon were like the hour and minute hand. Officially there are 88 recognized constellations, 48 of which were named by the Ancients. Although the names of these constellations are derived from Greco-Roman heritage, these are based upon Greek reinterpretations of the Babylonian, Sumerian and Egyptian patterns. Of great significance, Arabic astronomy flourished while European science was eclipsed for over a millennium. We still use the Arabic names for many of the brightest stars.
Who gave the stars their names is not critically important as the fact that all human cultures have looked to the sky for meaning, for portents, for solace.