The Roman alphabet reached Italy through Greek colonists in the south of the peninsula, whose alphabet the Etruscans, a non Indo European people occupying central Italy before Rome's rise, adapted for their own language sometime around the seventh century BC. Rome, initially a minor neighbour of Etruscan civilisation, took the alphabet in turn from the Etruscans and reshaped it further for Latin, dropping and adding a handful of letters along the way; the Etruscan alphabet, for instance, had no need for a letter G distinguished from K, and Latin's eventual G was a later Roman refinement of the letter C's shape.
Because the chain runs Phoenician to Greek to Etruscan to Latin, the Roman alphabet is, structurally, a great grandchild of the Phoenician abjad by way of two successive adaptations, each of which changed the letterforms, added or dropped characters, and in Greek's case introduced true vowel letters the Phoenician original never had. The twenty-six letter alphabet used for English today is itself a later expansion of the twenty-three letter classical Roman set, with J, U and W added during the medieval and early modern periods to distinguish sounds the Roman alphabet had originally let I and V do double duty for.