(FORTUNE Magazine) – One hundred years ago, dozens of department store chains fought for shoppers' attention. But after decades of consolidation--topped off by Federated's pending acquisition of May--the result is a monolith boasting nearly 1,000 department stores and revenues of around $30 billion. Here's a look at who swallowed whom along the way. -- Julie Schlosser

ALLIED STORES In 1928 Lew Hahn assembled a coalition of department stores including Jordan Marsh and Bon Marché; in 1935 the group was renamed Allied.

Major purchases Stern Brothers William H. Block

FEDERATED Formed as a holding company in 1929, its brand names included Abraham & Straus, F&R Lazarus, and Filene's of Boston.

Major purchases Bloomingdale's Bullock's, I. Magnin, Goldsmith's, Rike's, Burdines Rich's

MACY'S Rowland H. Macy opened his dry-goods store in New York City in 1858.

Major purchases Davison-Paxon-Stokes LaSalle & Kock Bamberger's O'connor Moffar Bullock's, I. Magnin

MAY David May launched his first store in the mining town of Leadville, Colo., in 1877.

Major purchases M. O'Neil William Barr Dry Goods A. Hamburger & Sons Bernheim-Leader Kaufman's Hecht's Daniels & Fisher Stores G.Fox Meier & Frank Associated Dry Goods** Foleys, Filene's Hess's, Thalhimers Wanamaker's, Woodward & Lothrop ZCMI, Strawbridge & Clothier Marshall Field's

Campeau Takeover* Allied Stores Macy's

Major purchases Liberty House Broadway Stores Joseph Horne

*Canadian developer Robert Campeau takes over Allied in 1986. Two years later he acquires Federated and drives both chains into bankruptcy. They emerge in 1992 under new leadership.

**Owner of chains including Lord & Taylor and J.W. Robinson's.