Porta Maggiore The Porta Maggiore ( " Larger Gate " ) , or Porta Prenestina , is one of the eastern gates in the ancient but well - preserved 3rd - century Aurelian Walls of Rome . Through the gate ran two ancient roads : the Via Praenestina and the Via Labicana . The Via Prenestina was the eastern road to the ancient town of Praeneste ( modern Palestrina ) . The Via Labicana ( now called the " Via Casilina " ) heads southeast from the city . The gate . The Porta Maggiore is by far the best urban site to visit for an understanding and view of the ancient aqueducts . It is a monumental double archway built of white travertine ( a type of limestone ) . It was first known as the Porta Prenestina , perhaps a reference to the road over which is passes ( the Via Praenestina ) . The " gate , " built in 52 by the emperor Claudius , was originally intended to provide a decorative section of support for two aqueducts , the Aqua Claudia and the Anio Novus . At that time these aqueducts crossed the ancient Via Labicana and Praenestina roads thereby providing the opportunity to create at this location a sort of triumphal arch to the conquest of nature and its conqueror , the emperor Claudius . The two channels of these aqueducts , ( the Aqua Claudia and Aqua Anio Novus ) , one lying on top of the other , can be seen when viewing the cross - section running through the travertine attic at the top of the gate . The gate was incorporated in the Aurelian Wall in 271 by the emperor Aurelian thus truly turning it into an entrance ( gate ) to the city . Experts refer to this as an early example of “ architectural recycling , ” essentially adapting one existing structure , to another use . In this case using an aqueduct as a wall . It was modified further when the emperor Honorius augmented the walls in 405 . The foundations of a guardhouse added by Honorius are still visible , while the upper part of the gate , as built by Honorius , has been moved to the left side of the Porta . It is currently known as the Porta Maggiore , possibly designated as such because of the road that runs through the gate leads to the Basilica di Santa Maria Maggiore . The church is an important place of prayer dedicated to the Virgin Mary . The following inscriptions in praise of the emperors Claudius , Vespasian , and Titus for their work on the aqueducts are prominently displayed on the attic of the Porta Maggiore : TI . CLAUDIUS DRUSI F . CAISAR AUGUSTUS GERMANICUS PONTIF . MAXIM . , / TRIBUNICIA POTESTATE XII , COS . V , IMPERATOR XXVII , PATER PATRIAE , / AQUAS CLAUDIAM EX FONTIBUS , QUI VOCABANTUR CAERULEUS ET CURTIUS A MILLIARIO XXXXV , / ITEM ANIENEM NOVAM A MILLIARIO LXII SUA IMPENSA IN URBEM PERDUCENDAS CURAVIT . IMP . CAESAR VESPASIANUS AUGUST . PONTIF . MAX . TRIB . POT . II IMP . VI COS . III DESIG . IIII P . P . / AQUAS CURTIAM ET CAERULEAM PERDUCTAS A DIVO CLAUDIO ET POSTEA INTERMISSAS DILAPSASQUE / PER ANNOS NOVEM SUA IMPENSA URBI RESTITUIT . IMP . T . CAESAR DIVI F . VESPASIANUS AUGUSTUS PONTIFEX MAXIMUS TRIBUNIC . / POTESTATE X IMPERATOR XVII PATER PATRIAE CENSOR COS . VIII / AQUAS CURTIAM ET CAERULEAM PERDUCTAS A DIVO CLAUDIO ET POSTEA / A DIVO VESPASIANO PATRE SUO URBI RESTITUTAS CUM A CAPITE AQUARUM A SOLO VETUSTATE DILAPSAE ESSENT NOVA FORMA REDUCENDAS SUA IMPENSA CURAVIT . Nearby archaeological remains . Close by the gate , just outside the wall , is the unusual Tomb of the Baker , built by Marcus Virgilius Eurysaces . In 1915 , a subterranean Neopythagorean basilica was discovered nearby on the Via Praenestina , dating from the 1st century . The groundplan shows three naves and an apse , a design similar to that which began to be adopted in Christian basilicas during the 4th century . The vaults are decorated with white stuccoes symbolizing Neopythagorean beliefs , although the precise meaning of elements of the decoration remains a subject of debate .