The Roman conquest of Dacia, a region that corresponds to present-day Romania, culminated in the formal establishment of Roman Dacia as a province. This significant change resulted from a series of military campaigns led by Emperor Trajan, who aimed to secure the Balkan territory and expand the Roman Empire's boundaries. After a series of rigorous military confrontations with the Dacian king Decebalus, which included the famous Dacian Wars lasting from 101 to 106, Trajan emerged victorious, bringing most of Dacia under Roman control. The final victory was solidified by Decebalus’ demise in 106, leading to the transformation of Dacia into a Roman province that would serve as a strategic military and economic asset for the empire.

The Romanization of Dacia initiated a vast swath of cultural changes for the local population. Roman colonization efforts, the introduction of Latin as the lingua franca, and the establishment of Roman law transformed the local governance structure and facilitated trade networks. Cities like Sarmizegetusa Regia were transformed into centers of Roman culture and administration. This newfound socio-political environment encouraged cultural exchanges that laid the foundations of modern Romanian society and language. Additionally, the conquest profited the Roman Empire through the acquisition of gold mines and other natural resources vital for its economic stability.

Roman Dacia at its peak extended across vast territories, encompassing not just present-day Romania but also surrounding regions. This novel division allowed for better governance and military defense, contributing to Rome’s efforts at maintaining order and promoting peace through law and economic development. The region remained under Roman rule for nearly two centuries, leaving an indelible mark on the local populace, architecture, and culture, which can still be traced in contemporary Romania.