The Plane Tree of Hippocrates is the huge, hollow plane tree on Platanos Square in Kos Town, at the foot of the walls of Nerantzia Castle. Tradition says that Hippocrates, the father of medicine, taught his students in its shade in the 5th century BC. The tree you see is not that old: most estimates put it at around 500 years, which still makes it one of the oldest living things in town.
The Plane Tree of Hippocrates at a glance
- Where: Platanos Square (Plateia Platanou) in Kos Town, on a raised terrace between Finikon Street and the ancient harbour excavations, opposite the Loggia Mosque.
- Planted: unknown; researchers estimate the present tree at about 500 years old, and 19th-century pictures already show it as an ancient, gnarled tree.
- What it is today: a living monument and the island's best-known symbol of Hippocrates, its branches held up by a frame of steel pipes.
- Time needed: 15 minutes, or an hour if you add Nerantzia Castle next door.
From Hippocrates to an Ottoman square
Hippocrates was born on Kos around 460 BC and is remembered as the founder of Western medicine, because he and his followers looked for natural causes of illness rather than divine punishment. The Hippocratic Oath still carries his name, although historians doubt he wrote it himself. After his time, the island built the Asklepieion, a healing sanctuary of the god Asclepius, whose terraces still stand on a hillside outside the town.
The square around the tree took its present shape much later. The Ottomans ruled Kos from the 1520s until 1912, and in 1786 they built the Loggia Mosque on the far side of the square; a marble fountain with an Arabic inscription records the date. An ancient stone sarcophagus beside the tree was turned into a fountain for washing before prayer. Over the last century the old trunk hollowed out and split, and the branches now rest on a steel frame and pieces of ancient marble that keep them from breaking off.
What to look for
- The trunk: hollow, split into several parts and coated on the inside with a reddish protective layer, yet it still comes into leaf every spring.
- The supports: a scaffold of steel pipes under the heavy branches, plus old marble fragments used as props.
- The sarcophagus fountain: an ancient marble sarcophagus under the tree, reused in Ottoman times as a fountain for ablutions.
- The Loggia Mosque across the square, from 1786, with its marble fountain on the north side; its roof was rebuilt in 1996 and it was damaged in the 2017 earthquake.
- The bridge to Nerantzia Castle, crossing Finikon Street, the palm-lined road that runs along the line of the castle's old moat.
Two legends under one tree
The story that Hippocrates taught under this plane is a legend: no ancient source places him at a particular tree, and the present one is far too young. A second legend says the apostle Paul preached here. The Acts of the Apostles do mention that Paul's ship called at Kos, but nothing records a sermon under a tree. The legend lives on in another way: seeds and cuttings said to come from the tree have been planted near medical schools and libraries around the world, including in Düsseldorf.
Tips for your visit
- Come early in the morning or in the evening, when the square is calmer and the light falls through the leaves.
- Don't climb on the supports or lean against the trunk: the tree is fragile, and the props are there for a reason.
- Walk round the tree before you take your photo: from the castle side you see the scaffold, from the mosque side the full crown.
Nearby
- Nerantzia Castle: the fortress of the Knights of St John on the harbour, reached over the bridge right beside the tree.
- Ancient Agora of Kos: the large excavated area of columns and foundations of the ancient city, a few minutes' walk away.
- Kos harbour: the old port below the castle, lined with boats for day trips to the nearby islands.
- Asklepieion: the ancient healing sanctuary on a hillside outside town, a short drive or bike ride away, with views across the sea to Turkey.
See Kos with World City Trail
Our Kos scavenger hunt turns the old town into a game you play on your phone. The route takes around 2 hours, with about 33 minutes of walking. The Plane Tree of Hippocrates is one of the stops, along with Nerantzia Castle. You can play in English, German, French, Italian, Dutch or Greek.
If you prefer a different format, there is also a self-guided walking tour and an outdoor escape game in Kos.
Take the self-guided walking tour of Kos →
Play the outdoor escape game in Kos →
Facts checked in October 2026.