Delos and Mykonos, the sacred island and its neighbour

From the harbour of Mykonos you can see Delos, a low, brown, rocky island across a narrow strait, with no village, no trees to speak of and no lights at night. It looks like nothing. For centuries it was one of the holiest places in the Greek world, and later a great market of the Mediterranean, and ruins cover much of it. Mykonos, the island everybody knows, was for most of that time its dull neighbour. The roles have reversed so completely that the little boat across the strait now carries visitors from the busy island to the empty one.

The island where Apollo was born

The story the Greeks told was that Leto, pregnant by Zeus and pursued by the jealousy of Hera, could find nowhere on earth willing to let her give birth. Delos, then a floating island drifting about the sea, took her in, and there, beside a palm tree, she bore Apollo. Most versions add his twin sister Artemis, though some put her birth on another island. In gratitude, the story goes, Delos was fixed to the sea floor and became sacred to the god.

Whatever the order of events, by the end of the seventh century BC Delos was a sanctuary that pilgrims, festivals and offerings came to from all over the Aegean. The most famous of those offerings still lines the way to the sacred lake: the Terrace of the Lions, a row of lean marble lions set up by the people of Naxos shortly before 600 BC. The figures standing on the terrace now are replicas; the originals that survive are kept in the island's museum, out of the salt and the weather.

Holiness had its own rules. In the fifth century BC Athens, which by then dominated the island, carried out a purification of Delos: the old graves were dug up and their contents moved across the water to the neighbouring island of Rheneia, and it was decreed that nobody should be born or die on Delos. The sick and pregnant women were taken over to Rheneia instead. The island was to belong to the god alone.

The market of the Aegean

The second life of Delos was commercial. In 166 BC, according to the geographer Strabo, Rome declared it a free port, partly to damage the trade of Rhodes, and merchants poured in: Greeks, Italians, Syrians, Egyptians, Jews, each with their own shrines and meeting halls. They built the houses whose floors you walk past today, many of them with courtyards and fine mosaics, and the theatre quarter that climbs the slope above the harbour. Delos also became, by the accounts of ancient writers, a great market for slaves.

The boom ended violently. In 88 BC the forces of Mithridates of Pontus, at war with Rome, sacked the island, and in 69 BC pirates allied to him attacked it again. Delos never recovered. By the second century AD the travel writer Pausanias could describe it as empty except for the guards of the sanctuary, and so, apart from archaeologists and the custodians of the site, it has remained. UNESCO made the whole island a World Heritage Site in 1990.

Visiting is simple and slightly regimented. Boats leave from the old harbour of Mykonos, usually in the morning, and the crossing takes about half an hour to forty minutes; the return times are fixed, and most visitors get two or three hours ashore. There is no hotel on the island and nobody stays the night. There is also very little shade, so a hat, water and good shoes matter more here than anywhere else on the trip. A strong meltemi, the summer north wind of the Aegean, can cancel the crossing altogether, which is worth bearing in mind if you have only one day.

The sensible route is the one the pilgrims used: up from the harbour along the Sacred Way into the sanctuary of Apollo, out to the lions and the dried bed of the sacred lake, then through the theatre quarter and, if there is time, up Mount Kynthos, the island's low summit. From the top the whole Cyclades lie in a ring around you, which is where their name comes from.

Mykonos, the neighbour

Mykonos has no ancient monuments to speak of. What it has is the look that sells the Greek islands: a harbour town of white cube houses and narrow lanes laid out, it is often said, to confuse pirates and the wind, the row of windmills on the ridge above the sea, and the old houses of the quarter known as Little Venice built right over the water. In high summer it is crowded, expensive and loud, and its fame as a party island is deserved. Out of season, and early in the morning in any season, the lanes of the town are as pretty as their photographs.

The two islands make a natural pair. Delos is the reason to go; Mykonos is where you sleep, eat and catch the boat.

Holidays that go there

Explore's thirteen-night Greek Island Wanderer is the one that reaches Delos. It starts in Athens and works through the Cyclades, with Syros, where Ermoupoli, Galissas and Kini are listed, then Paros, with Drios, Naoussa and Parikia, then Naxos, before Delos and Mykonos. It departs in April, May, June, September and October, which keeps it clear of the hottest weeks on a shadeless island.

Travelsphere's eight-night Classic Greece and Iconic Aegean Islands Cruise calls at Mykonos, with Kuşadası, Patmos, Heraklion and Santorini, and on the mainland Athens, Nafplion with its Palamidi Castle, and Epidaurus. Delos is not on its listed itinerary, so on that trip the sacred island is the low shape across the water from the harbour rather than a place you walk.

On either, the best hour in Mykonos is the first one of the day, before the boats and the heat arrive. On Delos it is any hour at all, with a hat on.