In 1510 Martin Fernandez de Enciso, following Alonso de Ojeda to the New World, took the survivors of Ojeda's colony of Nueva Andalucia (near the present Cartagena and east of Panama) and founded on the Tuira river the colony of Santa Maria la Antigua del Darien (commonly called Darien).
In September 1513 Nunez crossed the isthmus and (on the 25th or 26th) discovered the Pacific. Immediately afterwards he was succeeded by Pedro Arias de Avila, by whom Nueva Andalucia and Castilla del Oro were united in 1514 under the name of Tierra Firma, and who founded in 1519 the city of Panama, now the oldest European settlement op the mainland in America.
These highlands, with the mountains of Jaen and Almeria on the east, constitute Andalucia Alta or Upper Andalusia.
Andalusia consists of a great plain, the valley of the Guadalquivir, shut in by mountain ranges on every side except the S.W., where it descends to the Atlantic. This lowland, which is known as Andalucia Baja, or Lower Andalusia, resembles the valley of the Ebro in its slight elevation above sea-level (300-400 ft.), and in the number of brackish lakes or fens, and waste lands (despoblados) impregnated with salt, which seem to indicate that the whole surface was covered by the sea at no distant geological date.
The two territories designated respectively Nueva Andalucia and Castella de Oro were united in 1514 into the province of Tierra-firma, and entrusted to Pedro Arias de Avila.