The Collaborative International Dictionary of English v.0.48:

Cinquecento \Cin`que*cen"to\, n. & a. [It., five hundred,
   abbrev. for fifteen hundred. The Cinquecento style was so
   called because it arose after the year 1500.]
   The sixteenth century, when applied to Italian art or
   literature; as, the sculpture of the Cinquecento; Cinquecento
   style.
   [1913 Webster]