Zeus was the ruler of the ancient Greek gods.
In Religion, Lesson 5 it asks to translate: Zeus was the ruler of the ancient Greek gods.
The correct answer is given as: Ο Δίας ήταν ο αρχηγός των αρχαίων Ελλήνων θεών It doesn't accept Ζεύς instead of Δίας as a correct answer. Is it incorrect with Ζεύς?
Both should be accepted in Modern Greek, I believe.
Explanation of the form: the god's name in the nominative case in Ancient Greek is Ζεύς. But in Ancient Greek Z is pronounced DZ or ZD, and in fact the genitive is Διός (DZ > D), the accusative is Δία, and so on. This inconsistency was leveled over time, and the DZ/ZD of the nominative likewise simplified to a simple D .
Explanation of the form part two: the DZEUS pronunciation of really old Ancient Greek is itself a simplified form of a word that would sound something like DYEUS (where Y is the English consonant), which is cognate to the Latin Iupiter/Iouis (where the I is likewise the English Y consonant).