How did prepositions replace Latin case endings in Romance grammar?

In the transition from Classical Latin to the Romance languages, the complex synthetic system of noun case endings was largely abandoned in favor of analytic constructions.1

As Vulgar Latin evolved, the phonetic erosion of word-final sounds—such as the loss of final -m and the shortening of unstressed syllables—made it increasingly difficult to distinguish between different case forms through inflection alone. To maintain clarity, speakers began relying on prepositions to define the grammatical relationships between words that were previously signaled by case endings. For example, the prepositional phrase ad regem (to the king) replaced the dative case form regi.1

This shift toward analytic grammar meant that word order became the primary mechanism for conveying meaning, typically following a subject-verb-object structure. While most modern Romance languages have lost the Latin case system entirely, Romanian remains a notable exception, retaining inflected articles that distinguish between nominative/accusative and genitive/dative cases.23