The largest island in the south of Greece is called Crete, but note that Greece has over 3000 islands, so you may be thinking of a different.
its Crete. its underneath Sparta and is the island south to Greece.
Crete.
Crete
It is a large island to the south/south west of Greece. It is currently owned by Greece.
The capital city of the island of Corfu (part of Greece) is also named Corfu.
Crete
Crete
The largest island near Greece is Crete, it lies to the south east of Greece in the Mediterranean Sea
There are quite a few islands to the south of Greece, but you may be thinking of Crete which is the largest.
There is no French-controlled island south of Greece, or anywhere directly south. There are French Islands off the Madagascar coasts. The French island in the Mediterranean Sea is Corsica, just west of central Italy.
The island at the very bottom of Greece is called Crete and the there is a smaller island below it named Gavdos.
The literal answer to your question is Madagascar, a very large island off the coast of Africa which is about 3500 miles south (and 1100 miles to the east) of Greece. It is the largest island located south of Greece. I suspect, however, that what you are asking for the name of the largest of the Greek islands to the south of mainland Greece: that large island in the very south of Greece is Crete.