[CapitoliumJ. The Capitol in Rome acted as citadel and religious centre for the city from its beginnings. The Capitol comprised twin hillocks overlooking the Forum. On the northern of the two hills was a citadel, and on the southern the great temple of Jupiter Capitolinus. The temple, whose founding is traditionally attributed to the early king Tarquin, seems to have preserved its original 6th-century plan through successive rebuildings. The capital was approached by its own street, the Clivus Capitolinus. The Sibylline books were kept here, and rock-cut chambers underneath were apparently used as secret treasuries. Here too the consuls made their sacrifices and took their vows upon taking up office, and generals returning in triumph came to give thanks for their victory. The northern site, that of the citadel, is now covered by the church of Santa Maria in Aracoeli, while the site of the great temple is partly covered by the Palazzo Caffarelli.