There are quite a few islands to the south of Greece, but you may be thinking of Crete which is the largest.
It is a large island to the south/south west of Greece. It is currently owned by Greece.
its Crete. its underneath Sparta and is the island south to Greece.
The Greek island of Lindos can be found of the farthest south eastern border of Greece in the Aegean Sea. It is 50km south of the town of Rhodes on the Island of Rhodes.
The largest is Crete, althought there are more than a couple
Crete.
Crete
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.
Crete
Crete
The largest island near Greece is Crete, it lies to the south east of Greece in the Mediterranean Sea
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 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.