
The "Culture" article (5) explains the name Trellos and the lion. Here we stay with the stories around Kaisariani Monastery and the life of the mountain's people. Each story is marked as historical record, tradition or unverified.
The spring and Aphrodite. Greek Wikipedia says a spring with plentiful cold water used to flow near Kaisariani Monastery, probably the one called "Kallia" by ancient Greek and Roman poets. A little higher up, the place in antiquity was dedicated to Aphrodite and called "Kyllou Pera", today "Kallopoula". The "probably" is the source's own, and the article carries a notice of insufficient sourcing. English Wikipedia says the site was "probably" dedicated to Aphrodite.

The monastery. The present church (katholikon) dates to around 1100 and is dedicated to the Presentation of the Theotokos. The area of today's Kaisariani grew around it. The monastery was closed in 1833 under the Bavarian regency, because fewer than six monks lived there. According to the article, the frescoes of the church date to 1682 (Ioannis Ypatos, funded by the Benizelos family).
Mehmed and the key. According to the French doctor Jacob Spon (1675), Sultan Mehmed II went to the monastery in 1458 and was given the key to the city there. Both Wikipedias present it as Spon's account, not as a confirmed fact.
The monks and the herbs. The monastery's income rested on olives, vines and beehives. The monks were known for medicines made from herbs. In 1209, according to the article, Michael Choniates complains that he received no income from the monastery's beehives, and the abbot replied that they had been destroyed. The reference is marked as incomplete.

The library legend. According to the council of elders of the time, as Wikipedia quotes them, the monastery's manuscripts were sold to the English as parchment and the rest were used in the metropolis's kitchens. Another account says that during the fall of Athens they were used as fuses on the Acropolis. Both accounts are unsourced in the article. We present them as oral and later memory.
Zeus Ombrios. English Wikipedia mentions a sanctuary of Zeus Ombrios at the summit, with many offerings especially of the 8th and 7th centuries BC. It lies within a military installation and is not accessible. "Ombrios" means "rain-bringer". This fits the mountain's place on Athens' horizon, but a link to popular customs was not documented.
The Lion and Koutouki caves. The Liontari cave takes its name from the local tradition of the lion of Hymettus (see article 5). The Koutouki cave, above Paiania, is the largest on the mountain. For popular stories around Koutouki we found no documented source.
Papadiamantis. According to excerpts of Greek Wikipedia that turned up in a search, a tradition about a spring of Hymettus gave Alexandros Papadiamantis the occasion for his short story "The miracle of Kaisariani". We did not open the story or read the tradition itself, so we do not reproduce it.
Not verified: (1) The content of the spring tradition and of Papadiamantis's story. (2) Popular festivals, customs and place names (for example Kallopoula) beyond those mentioned. No folklore collection was checked. (3) Present-day beekeeping on Hymettus, the small chapels and their feast days. (4) The accounts of Mehmed and the manuscripts, which come from later or unsourced testimony. Primary sources worth checking: folklore archives (for example the Academy of Athens), the Ministry of Culture, the Municipality of Kaisariani. If you have your own story or family memory, it can be added with your consent.
Sources
- Wikipedia (Greek), Μονή Καισαριανής: https://el.wikipedia.org/wiki/Μονή_Καισαριανής
- Wikipedia, Kaisariani Monastery: https://en.wikipedia.org/wiki/Kaisariani_Monastery
- Wikipedia (Greek), Υμηττός: https://el.wikipedia.org/wiki/Υμηττός
- Wikipedia, Hymettus: https://en.wikipedia.org/wiki/Mount_Hymettus
- Ministry of Tourism, Odysseus, Lion cave of Hymettus: http://odysseus.culture.gr/h/2/gh251.jsp?obj_id=16861