Until around 1950, Quinta Monte São Sebastião consisted essentially of olive trees and some vacant lots. After that date, vines were planted taking advantage of the good sun exposure, the terraces, and an olive grove, almond grove and other associated fruit trees were planted. At the same time, construction began on the house, a typical wine-growing house with traditional wine presses in the basement, and where the Quinta's wine began to be made. Later, an alembic was built and a small house that served as housing for the workers of the Quinta. For the time, and due to its privileged location, abundant labor and material resources, Quinta Monte São Sebastião was considered a cutting-edge agricultural exploration.

In the following decades, the family always sought to maintain and increase its wine heritage, as well as being concerned with the sustainability of the farm. The vineyards and olive trees on the Quintas are in the process of Integrated Production, which is why we respect certain standards in order to guarantee environmental protection.

For several decades, the Quinta's main activity was the production of grapes for the prestigious Port Wine companies. Until, in 2006, with the renovation of the house and the inauguration of an Agrotourism accommodation unit, the first bottled wine was created with the Quinta's own brand.

Currently, the farm at Quinta Monte São Sebastião is made up of several farms, occupying a total area of ​​50 ha, of which around 35 ha are used for wine production, which is the main agricultural activity on the farm. The remaining area is occupied by olive groves, orchards and almond groves. Over time, Quinta Monte São Sebastião has remained in the hands of the Breia family, always with the same objective: to preserve, expand, improve and innovate.