In Republican times the area occupied by the Imperial Forums was a vast residential zone extending over the Oppius, Viminal,Capitoline and Quirinal hills. When, during the Imperial period, the Roman Forum became too small to cope with normal public business it was decided to take over this land for a new forum. The Forum of Julius Caesar was built between 54 and 46 B.C.; the other four were built afterwards. These new forums soon supplanted the old one, and became the new centre of civic life. However, in the Middle Ages the same fate befe11 the new forums, which deteriorated to a heap of ruins, a handy quarry and a squatter's paradise. Archaeological excavations this century have brought to light many of the ancient structures; but a great deal remains to be excavate.

The tour begins from the left of the Monument to Victor Emmanuel II in Piazza Venezia, by the churches of Santa Maria di Loreto (begun in 1507 by Antonio Sangallo il Giovane, in Renaissance style, and finished by Iacopo del Duca) and SS Nome di Maria (built in 1738 by Deriset).

Forum of Trajan. Below street level, it is entered from Piazza Foro Traiano. Chronologically the last and most splendid of the Imperial Forums, it was designed by Apollodorus of Damascus. Covering an enormous square it boasted two libraries, temples, basilicas and monuments. Today some ruins of the BasiLica ULpia (for public gatherings) remain, together with Trajan.s Column, erected in 113 in Trajan's honour - almost intact, it is the most characteristic monument in the Imperial Forums. The column is 38 metres tall and covered with a spiral frieze depicting the Emperor's military exploits in the lst cent. A.D. against the Dacians. 

It rests on a plinth containing the Emperor's sepuchral vault. The statue of St. Peter at the top was raised in the 17th century by Pope Sixtus V.

TraJan's Market. An impressive group of buildings annexed to the Forum of Trajan where the people gathered to gossip and keep up with events. The vast semicircle where the merchants displayed their goods was also designed by Apollodorus of Damascus. On busy days the market extended as far as the Torre delle Milizie. Today the superb PaLace of the Knights of Rhodes, (end of the 12th cent. with 15th cent. restoration work) stands on the ruins.