Galla Placidia (386 - 450 AD), sister of the Roman Emperor Honorius who had transferred the Capital of the Western Empire from Milan to Ravenna in 402 AD, built this little Mausoleum with a Latin cross plan around 425-450 as her own resting place. However, the mausoleum was never used for that purpose, because the empress died and was buried in Rome in 450.he outside of the building is very sober compared to the magnificence of the inside, decorated with mosaics made even brighter by the golden light filtering through the alabaster windows. The lower surfaces of the interior are covered with marble slabs, while the upper part of the building – including the walls of the vault, the lunettes, and the cupola - is entirely decorated with mosaics. The atmosphere of the Mausoleum of Galla Placidia is undoubtedly magical. The countless stars of the cupola have deeply stirred the imagination of many visitors of Ravenna, for instance, Cole Porter who, during his honeymoon in the city, was so impressed by the starry sky of the small mausoleum that he wrote his famous song Night and Day.