sentences:  The building stood in front of the southern Acropolis wall and was "circa" 43 m long and 14 m wide, fronted on its northern long side by a portico of 4.5 m width.To make room for that portico, the southernmost portion of the rock-cut steps leading up to the west facade of the Parthenon had to be cut away.Thus, the portico is assumed to have been an early fourth century BC addition, while the main part of the structure is thought to be roughly contemporary with the Parthenon, i.e.