Vatican City
The name was first used in the Lateran Treaty, signed on 11 February 1929, which established the modern city-state. The name is taken from Vatican Hill, the geographic location of the state. "Vatican" is derived from the name of an Etruscan settlement, "Vatica" or "Vaticum" meaning garden, located in the general area the Romans called "vaticanus ager", "Vatican territory".
Catholic Church and ecumenism
The Catholic Church recognizes 21 Ecumenical or General Councils: Nicaea I (325), Constantinople I (381), Ephesus (431), Chalcedon (451), Constantinople II (553), Constantinople III (680–681), Nicaea II (787), Constantinople IV (869–870), Lateran I (1123), Lateran II (1139), Lateran III (1179), Lateran IV (1215), Lyons I (1245), Lyons II (1274), Vienne (1311–1312), Constance (1414–1418), Florence (1438–1445), Lateran V (1512–1517), Trent (1545–1563), Vatican I (1869–1870), Vatican II (1962–1965).