There , the main doorway , sheltered by a portico .
The two side doorways opened to a vestibule , 50 feet ( 15 m ) wide and 15 feet ( 4.6 m ) deep , which was divided by screen colonnades into three compartments .
There , the main doorway , sheltered by a portico , and the two side doorways opened to a vestibule , 50 feet ( 15 m ) wide and 15 feet ( 4.6 m ) deep , which was divided by screen colonnades into three compartments .