Hippo Regius occupied a sheltered coastal setting near modern Annaba, where maritime routes met the agricultural hinterland of northeastern Algeria. The town had a long pre-Roman history involving Phoenician contacts and Numidian kingship, reflected in its designation as royal Hippo. Its exact earliest foundation date is uncertain. Roman control brought new civic institutions and monumental construction without erasing older regional traditions. The archaeological remains below the modern basilica belong to this ancient city, while the church on the hill is a much later memorial to its most famous bishop.

Under Roman rule, Hippo became a prosperous port with public baths, a theater, a forum, temples, houses, streets, and water infrastructure. Agricultural produce, trade, administrative work, and local craft sustained its economy. Wealthy residences displayed mosaics and sculpture, while inscriptions record offices, benefactions, and religious practices. These remains reveal a varied urban society rather than merely the background to one celebrated individual. The city's location connected it with other African ports and the wider Mediterranean, making maritime exchange central to both its prosperity and its exposure to political change.

Augustine arrived at Hippo in 391 and became a priest, then bishop in the 390s. He preached, administered church affairs, engaged in theological controversies, and wrote works that profoundly influenced Latin Christianity. His responsibilities also involved disputes, charity, property, and the practical needs of a congregation within a complex African society. In 430 he died while Vandal forces besieged the city. The conquest and subsequent changes altered Hippo's institutions, though occupation continued through later periods rather than ending completely with Augustine's death.

The ancient city gradually lost prominence as settlement shifted toward the site of modern Annaba. Excavation under French colonial rule exposed major monuments and Christian buildings, while interpretations often emphasized Roman and Christian connections with Europe. Construction of the hilltop Basilica of Saint Augustine began in 1881 and was completed around 1900. Its architecture combined stylistic references to early Christian and regional traditions. The basilica renewed devotion to Augustine while also belonging to the religious and political setting of colonial Algeria, making its own history distinct from that of his original church.

Today the ruins, archaeological collections, and basilica together present more than two millennia of urban and religious memory. Conservation must manage vegetation, water, mosaics, exposed masonry, and the interpretation of excavated buildings whose functions are not always certain. The modern church remains a place of worship as well as a landmark above the ancient site. Hippo Regius is significant for its Numidian and Roman urban history, Augustine's African ministry, and the later ways his memory was reclaimed, monumentalized, and reinterpreted within a changing Algerian landscape.