Who is credited for ushering in the Hellenistic period???

Alexander the Great credited the Hellenistic period

for (a) a tragedy was considered a main greek drama and it influenced alot of others. for (b) the actors in greek theater were named as aeschylus, sophocles, and euripides and sometimes playwrites. for (e) in a semi-circular theater called the "orchestra.". we'll the question was explain where the namer actors originated.

hope this : d

i really dont know the answer