How are Romance languages related to the Indo-European language family?

The Romance languages are a subgroup of the Italic branch of the Indo-European language family.1

This relationship is defined by a clear genealogical lineage: the Romance languages—such as French, Italian, Spanish, Portuguese, and Romanian—are all direct descendants of Latin, the principal language of the Italic branch.12

As members of the broader Indo-European family, these languages share fundamental characteristics with other branches, such as Germanic, Slavic, and Indo-Iranian. These similarities include shared vocabulary and grammatical structures that can be traced back to a common, reconstructed ancestor known as Proto-Indo-European, which is believed to have been spoken around 4000 BCE. While the Romance languages evolved from Latin within historical times, their inclusion in the Indo-European family is established through systematic phonetic and structural correspondences that link them to the family's ancient roots.3415