I assume you mean Roman Catholic. If so, then:
No, Greece is largely Greek Orthodox.
As an anglo-catholic I believe that Orthodox Christians are members of a valid branch of the one, holy catholic and apostolic church. But they are not roman catholic.
No. The time period for what we refer to as Ancient Greece had ended before Catholicism began.
Today most of Italy is Roman Catholic and Greece is mostly Greek Orthodox.
It's unlikely that Wiccans fought alongside the Catholic Church against Protestant beliefs since the time of Greece, as Wicca is only less than a century old. Besides that, Greece is predominantly Orthodox Christian, not Catholic or Protestant Christian.
it's still Catholic but it's in the Eastern rite
Greek Orthodox: Bulgaria, Greece, Romania, Serbia Catholic: Croatia, Hungary, Austria
In the Middle Ages the whole of Western and Central Europe was Catholic. Eastern Europe, Greece and much of modern Turkey was Orthodox. roman catholic when the church took over.
Yes, the nation of Greece is 98% Greek Orthodox, which is one of the oldest branches of the Oldest Christian Church. The orhodox faith differs from the Catholic in hierarchal structure as well as spiritual tradions, but teachings and dogma are pretty similar. Other 2% of Greeks are from the Catholic, Jewish, or Islamic Faith mostly from the Islamic and Jewish faith.
There were no Dark Ages in the Catholic Church, and as of the late 20th century, secular historians have come to recognize that there really was no Dark Age, and that this label was just one of ignorance of earlier historians. You will need to reword your question.
I think you are looking for the "Eastern Orthodox" church. It may be described very very roughly as a Catholic, Apostolic church that does not feel the need for the same hierarchical structure as say the "Roman Catholic" church.
Christianity, specifically Roman Catholicism, is the most common religion in southern Europe. Countries like Italy, Spain, Portugal, and Greece have a majority of their population identifying as Catholic.
This question is mistaken. The Protestant Reformation came along way after the Ancient Greek period.
The majority of the population in Greece is ethnically Greek, making up around 98% of the population. There are also small minority groups such as Albanians, Turks, and Romani people.