Nemrut (volcano) of the earliest trade routes. Two eruptions of Nemrut were probably witnessed by people of Urartu, an ancient state located in the eastern Turkey. These eruptions occurred c. 787 BC (period of King Menua) and c. 657 BC (period of King Rusa II), and the latter eruption might cause the sudden disappearance of the city Uaiais located 30 km east of Süphan. In the 1980s, Japanese volcanologists studied the evolution of gases inside the caldera of Nemrut. They found that the ratio of helium isotopes He/He is 1.06, which indicates volcanic activity (most of the measured helium evolved from the
Theydon Mount derives from the hill which it is located. Theydon Mount has been called "Theydon Paulyn", "Theydon Lessington", and "Theydon Briwes" in the past. The names from the former lords of the manor. The name Thoydon Mount has also been used. Theydon Bois, Garnon and Mount were recorded in the Domesday Book as "Taindena"/"Teidana". Hill Hall is a Grade I Listed country house. It was built in 1557-8 for Sir Thomas Smith. Theydon Mount has a church called St Michael which was completed in 1614 by Sir William Smith and is Grade I Listed. The original church was St Michael and