Rome came into direct contact with the Histri, the indigenous inhabitants of the Istrian peninsula, in the closing decades of the 3rd century BCE. Wars for supremacy in the northern Adriatic lasted, with varying fortunes, through to 177 BCE, when after an exhausting months-long siege, the Roman army seized Nesactium, the primary Histrian settlement and the seat of their king Epulon. Over the course of the 2nd and 1st centuries BCE, the Histri gradually adopted Italian products and customs through trade exchange, without substantially changing their traditional way of life. The turning point in the Romanisation of Istria occurred during Caesar's time, in the mid-1st century BCE. This was the time of the survey and cadastral division of arable land, annexed to newly founded Roman cities. Old Histrian fortified settlements and ports on the western coast of Istria, Pola and Parentium, became colonies of Roman citizens and vibrant centres of social, religious, and commercial life. They were settled by newcomers from Italy, but also by numerous slaves born in distant Greek, eastern, and African provinces, whose descendants would acquire Roman citizenship over several generations, creating the cosmopolitan atmosphere characteristic of Roman port cities.
Roman colonies were a rapid gateway for the wholesale introduction of a monetary economy based on the unified Roman currency and measurement system, the adoption of Latin script and language, Roman and Greek names, customs, and beliefs. Pula became the largest, richest, and most important city in Istria, boasting two theatres and an amphitheatre. Forum temples, city gates, the Arch of the Sergi, and walls were further attractive features of Pula. Natural resources, materials, and products from all the provinces along the Mediterranean shores found their way to Istria via the maritime trade. The Roman Period Collection thus presents vases made of Egyptian alabaster, plates produced in North Africa and central Italy, amphorae and lamps from Greek islands, sculptures carved from white Greek marble or the white-to-grey marble brought from the shores of the distant Sea of Marmara. Istria's primary products—exported by sea, river, and land to northern Italy and the provinces of Pannonia and Noricum—were olives, olive oil, amphorae, fish products, wine, wool, and white limestone suitable for construction. Smaller everyday items made of ceramics, stone, iron, and bronze, vessels, equipment, and tools useful in households and daily life were produced for local needs in craft workshops located in Istrian towns and in the countryside.