The lower portion of this triangular area, a vast domain of more than half-a-million square yards, sloping gradually to the silver shores of the Sea of Marmora, was reserved for the imperial palaces and gardens. Running parallel with the imperial palace, to the north, was the Hippodrome, into which the story of the Empresses will repeatedly take us. Like the Great Circus at Rome, on the model of which it was built, it was the most commanding and venerated institution of the frivolous people. Its spacious long-drawn arena was flanked by tiers of seats which could accommodate tens of thousands of people--some authorities say a hundred thousand people. A lofty imperial gallery, the _kathisma_, surveyed the races and the spectators from the north-eastern end, and a great purple awning gave protection from the burning sun. Beyond the Hippodrome and the palace was the chief square of the city, the Augusteum, which corresponded to the old Forum at Rome or the Agora at Athens. Under the shelter of the double colonnade which surrounded it the idlers of Constantinople held their endless fiery discussions of the last chariot race, the last heresy, or the last revolution: the studious bargained for books: the amorous made traffic in love. It was the heart of the city. On the south side of it was the great gate of the palace: on the north side the church, or cathedral, of St Sophia: the Senate House faced it on the east: and from its western side ran the main street of Constantinople, the Mese (or Middle Street), lined with colonnades, which passed more or less continuously along the central ridge of the triangular area which the city occupied. A city was, in those days, and for many a century afterwards, a palace and a cathedral: we can only say of the million citizens that they were packed into the spaces not occupied by Church or State, especially in the region between the Mese and the Golden Horn, where fire and pestilence periodically fed on their crowded tenements.