Hellenistic vs Hellenistical

Of or relating to a Hellenist. 

Of or relating to the period of the Greek culture, history, or art after the death of Alexander the Great (323 B.C.) to the defeat of Cleopatra and Mark Antony by Octavian (31 B.C.) – though this end-point is often debated, and can range from 146BC to 330ADhttps://en.wikipedia.org/wiki/Hellenistic_period. 

Hellenistic