The bustle era had two bustle periods with a lull in between them. The dates are arbitrary. Bustles evolved from crinolines in 1870 by confining the flared fullness to the back and stayed in style through 1874. The first bustles flared out and down from full skirts. Silhouettes became columnar and tight in 1875 with flaring confined to the back beginning at about a height just above the knee, at first retaining the exuberant frills of the crinoline era. Dresses became simpler around 1880 and A-line skirts and hourglass figures appeared. But bustles came roaring back around 1884, subsiding by the end of the decade. The second wave bustles erupted back and could even swell aggressively upward, before falling behind a columnar or A-line skirt. The dresses themselves were often relatively plain. Small bustles remained in use to add fullness to the backs of floor-length dresses, a function they still serve in evening and wedding dresses today.