Five recently renovated galleries are now home to some of the oldest and most precious pieces at the MFA Boston. The art and artifacts that comprise Early Greek Art, Roman Portraiture, Gods and Goddesses, and the Byzantine Empire are now on view in these new second-floor spaces. The Gallery of 20th- and 21st-Century Art, which features modern work influenced by classical culture, includes five sculptures and one painting by the American artist Cy Twombly. The largest of the galleries is devoted to Greek art made from the 10th century B.C. through the end of the Persian Wars. —J.D.