<P> Just as uncertain is the nature of the sacrifices made there . Judging from the remains of the actual, relatively small fire altar inside the huge altar edifice, it can at least be concluded that its shape resembled a horseshoe . It was apparently an altar with two projecting side wings and one or several steps in front . Possibly the thighs of sacrificial animals were burned here . But it is just as possible that the altar served only for libations--the offering of sacrifices in the form of incense, wine and fruits . It is likely that only priests, members of the royal household and illustrious foreign guests were allowed access to the fire altar . </P> <P> Already Attalos I began to remodel the acropolis of Pergamon . In the course of time the original structures were augmented by a Dionysus temple, a theater named after Dionysus, a heroon, an upper agora for the city, and the great altar known today as the Pergamon Altar . There were also several palaces, and a library in the Athena sanctuary . </P> <P> Probably in the 2nd century, the Roman Lucius Ampelius recorded in his liber memorialis ("Notebook"), in Chapter VIII (Miracula Mundi), "At Pergamum there is a great marble altar, 40 feet (12 m) high, with colossal sculptures . It also shows a Gigantomachy". </P> <P> Besides a comment by Pausanias, who compares sacrificial practice in Olympia with that in Pergamon, this is the only written reference to the altar in all of antiquity . This is all the more surprising because the writers of antiquity otherwise wrote a great deal about such works of art and Ampelius, after all, considered the altar to be one of the wonders of the world . The absence of written sources from antiquity about the altar has given rise to a number of interpretations . One possibility is that the Romans did not regard this Hellenistic altar as important since it did not date from the classic epoch of Greek, especially Attic, art . Only this art and later evocation of the associated values were considered significant and worth mentioning . This view was held particularly by German researchers starting in the 18th century, especially after the work of Johann Joachim Winckelmann became known . The only graphic representations of the altar are on coins of the Roman Empire, which show the altar in a stylized form . </P>

The chief religious shrine of pergamon is the altar of apollo