Milreu developed near modern Estoi in the fertile countryside behind the Algarve coast. From the first century CE, a rural estate participated in the economy of Roman Lusitania, drawing on farmland, water, local roads, and connections with the port of Ossonoba, now Faro. Its earliest buildings were repeatedly replaced, so the visible ruins represent several generations of investment. The estate combined agricultural production with elite residence, allowing its owners to display urban tastes while drawing wealth from the work of the surrounding countryside.

During the later Roman period, especially around the fourth century, the residence acquired an impressive arrangement of rooms around a colonnaded courtyard. Mosaics, marble decoration, painted plaster, sculpture, and private baths signaled the household's social standing. Marine imagery, including fish and other sea creatures, decorated floors and bathing spaces. These designs brought Mediterranean artistic conventions into a provincial estate. Kitchens, service areas, presses, and storerooms belonged to the same working complex, even though luxurious rooms have attracted more attention from visitors and early excavators.

A substantial sanctuary beside the house is among Milreu's most distinctive remains. Its elevated masonry, water-related decoration, and surrounding installations suggest a ceremonial landscape that connected religious activity with the estate's social authority. Precise interpretations have changed as excavations distinguished construction phases. The building later became a Christian place of worship, with alterations supporting new rituals and burial practices. This conversion demonstrates continuity of place through changing belief rather than the wholesale replacement of one population or an abrupt end to rural life.

Occupation continued beyond the Roman Empire, through late antiquity and into the Islamic period, when parts of the complex were used for burial. Buildings gradually deteriorated, and later farming and domestic construction reused the site. A more recent rural house stands over ancient remains, making centuries of adaptation visible. Nineteenth-century investigation, especially work associated with Estácio da Veiga, recovered mosaics and sculpture and established Milreu's archaeological importance. Subsequent Portuguese and international research refined the sequence and challenged interpretations based only on monumental appearance.

Milreu is protected as an archaeological site with an interpretation center explaining the estate's long development. Exposed mosaics, plaster, masonry, and buried deposits require care against rain, roots, salts, temperature changes, and visitor contact. Finds also survive in regional museum collections, linking the villa with the broader history of the Algarve. Its significance lies in the relationship between production and display: agricultural labor financed refined interiors, while a sanctuary, Christian conversion, Islamic burials, and later houses show how one rural property remained useful across profound political and religious changes.