When did the mask begin to be used in greek theatre?

Masks began to be used in Greek theatre during the 6th century BCE, with their use becoming prominent in the performances of tragedies and comedies. These masks allowed actors to portray multiple characters and express different emotions clearly to large audiences. Made from materials like wood, linen, and clay, they were essential for both visibility and the conveyance of character traits in the open-air amphitheaters of ancient Greece.