The Artemis worshipped at Ephesus was not the Greek huntress with her bow. She was a great goddess of the Anatolian type, absorbed into a Greek name, and her cult image showed her rigid and pillar like, wrapped in animals, with rows of oval objects across her chest that have been read as breasts, as bull testicles from sacrifice, as gourds and as amber ornaments. No reading commands agreement, which is itself informative: the image was old enough that the people who copied it were no longer sure what it meant.
Her temple was among the largest Greek buildings ever raised and was counted a wonder of the world. It burned in 356 BCE, according to the story at the hands of a man who wanted his name remembered, and the Ephesians rebuilt it grander. Like other great sanctuaries it functioned as a bank and a place of asylum, and its estates and treasure made it a power in the city's affairs rather than an ornament to them. A month of the calendar and an annual festival were hers, and images of the goddess in silver and other materials were made for pilgrims to take home.
That trade is what produces the confrontation described in Acts, where a silversmith argues that the new preaching threatens both the goddess and the livelihood of those who work for her, and a crowd fills the theatre for two hours chanting her greatness. Ephesus was also a warden of temples of the imperial cult, so the city held the machinery of two religions of scale at once.