Located in the former territory of the Callaici Bracari, the granite rock fountain/spring has Latin inscriptions, dedicated to the Gallaecian and Lusitanian gods Tongoenabiagus and Nabia (built during the era of Roman Emperor Augustus).

[2] In the 18th century, the accountant D. Jerónimo Contador de Argote, noted in his records: "behind the church of São João Marcos is a garden, that is called "Idol", in which is located a deep spring, which has a rock, which appears to be living rock, with a figure in long robes, that is five palms [in size]: it looks like [the figure] has a long beard, and part of his body is missing; his right hand is broken and on the left the form of a envolotório, and above the head there are letters..."[2][3] Jerónimo recounts with this detailed description, a design of the fountain of the Idol that was first created by the Bishop of Urianópolis, Alves de Figueire.

[2][3] A year later, King Pedro V and the marquess of Sousa examine the fountain, then offered to the monarch as a gift by its owner João de Abreu Guedes do Couto.

[2][3] Leite de Vasconcelos made return visits in 1903 and 1905 to study the fountain further, hypothesizing that the human figure on the left was the religious practitioner and the image within the structure the divinity.

[2] But, they transferred this title to the State the following year, including the fountain, the surrounding lands and access along Rua do Raio: the Direcção Geral dos Edifícios e Monumentos Nacionais (DGMEN) then demolished the public tank, water pipes, encountered an imbrex and tegula and votive inscription.

It was followed in 1999 by an archaeological investigation of the surrounding area, and a 2000-2001, project by architect Paula Silva, in collaboration with Carla Pestana and João Ferreira, to construct a building to preserve the site and act as interpretative centre.

[4] It was followed in 2003 by a formal excavation by the Archaeology department of the Universidade do Minho, coordinated by Francisco Sande Lemos and José Manuel Freitas Leite, with the collaboration of Liliana Sampaio, Sandra Nogueira, Ricardo Silva and Artur Jaime Duarte, who were responsible for the discovering drainage canals and Roman wall structures.

[2] On the conclusion of the construction project, in 2004, the site fell under the authority of the DGEMN, the municipal government of Braga, the Universidade do Minho and the D. Diogo de Sousa Regional Museum, through a protocol between the identified parties.

[2][4][9] Francisco Sande Lemos, suggests that the fountain was paired with the sanctuary of Fragas de Panóias in Vila Real, one of the more familiar monuments of Roman rock-art epigraphy in the Iberian northwest.