From Project Athinai
The Stoa Basileios (Royal Portico) was erected around 500 BC. The Persians captured the city in 480 BC and destroyed most of its buildings. However, the Athenians managed to repair the Stoa Basileios and it continued to be in use throughout the Classical Period. It was the seat of the administration of the Archon Basileios the second-in-command magistrate elected for one year. He was responsible for the administration of the Mysteries, of the Epilenaia (festival of Dionysos), of the torch races and of many sacrifices. He was also responsible to judge lawsuits involving homicide and impiety.
The stoa was located at the northwest corner of the Agora. Drako's and Solon's laws were written on the inner walls of the stoa and on stelai in front of it. The stoa measured 7.18 m deep by 17.72 m wide. The north, west and south walls consisted of poros ashlar masonry on a 0.56 m high platform projecting 0.85 m from the walls. There were four poros Doric columns inside the stoa. The east side of the stoa consisted of a row of eight poros Doric columns on two steps. The three intercolumnar spaces on the south were closed by wooden rails and posts at midpoints.
There were two sculptural groups on the roof of the stoa: Theseus hurling Skiron into the sea and Hemera carrying Kephalos.
The block of limestone where magistrates stood to take their oath was located just in front of the north end of the stoa, close by the north wing (Fig. 44). It measured 0.95 m. wide, 2.95 m. deep and 0.40 m. high.
A collection of Herms stood in front of the north end of the stoa.
In front of the stoa, stone steps were aligned with the north (2 steps) and south walls (3 steps). They contained a levelled terrace. Poros thrones were available for prominent citizens.
At the end of the 5th century, wings were added in front of the stoa. The facade of each wing consisted of three columns.
A marble statue of Themis was erected in front of the stoa around 325 BC by a group of citizens who had assumed the charge of Royal Archons.
American School of Classical Studies at Athens; The Athenian Agora: A Guide to the Excavation and Museum, 1990
Camp, John M.; The Archaeology of Athens, Yale University Press, 2001, pp. 44-45
Connolly, Peter and Hazel Dodge; The Ancient City - Life in Classical Athens & Rome, Oxford: Oxford University Press, 1998
Davis, W. S.; A Day in Old Athens, 1910
Travlos, John, Pictorial dictionary of Ancient Athens, Books that matter, New York, 1971, p. 580