In the Ionic capital, spirally coiled volutes are inserted between the abacus and the ovolo. This order appears to have been developed contemporaneously with the Doric, though it did not come into common usage and take its final shape until the mid-5th century BC. The style prevailed in Ionian lands, centred on the coast of Asia Minor and Aegean islands. The order's form was far less set than the Doric, with local variations persisting for many decades. In the Ionic capitals of the archaic Temple of Artemis at Ephesus (560 BC) the width of the abacus is twice that of its depth, consequently the earliest Ionic capital known was virtually a bracket capital. A century later, in the temple on the Ilissus, the abacus has become square (See the more complete discussion at Ionic order). According to the Roman architect Vitruvius, the Ionic order's main characteristics were beauty, femininity, and slenderness, derived from its basis on the proportion of a woman.