what was the purpose for this meeting?
To nominate Winfield S. Hancock for president and William H. English for vice president in the US presidential election of 1880.
Introduction
The 1880 Democratic National Convention was held June 22 to 24, 1880, at the Music Hall in Cincinnati, Ohio, and nominated Winfield S. Hancock of Pennsylvania for president and William H. English of Indiana for vice president in the United States presidential election of 1880.

on what date did the 1880 democratic national convention occur? June 22 to 24, 1880
To select candidates for the United States presidential election of 1880 It nominated Winfield S. Hancock of Pennsylvania for president and William H. English of Indiana for vice president in the United States presidential election of 1880. Nomination of candidates for the president and vice president in the United States presidential election of 1880.
1880 Democratic National Convention 1880 Democratic National Convention 1880 Democratic National Convention
Introduction Introduction Introduction
and nominated Winfield S. Hancock of Pennsylvania for president and William H. English of Indiana for vice president in the United States presidential election of 1880. The 1880 Democratic National Convention was held June 22 to 24, 1880, at the Music Hall in Cincinnati, Ohio, and nominated Winfield S. Hancock of Pennsylvania for president and William H. English of Indiana for vice president in the United States presidential election of 1880.
 The 1880 Democratic National Convention was held June 22 to 24, 1880, at the Music Hall in Cincinnati, Ohio, and nominated Winfield S. Hancock of Pennsylvania for president and William H. English of Indiana for vice president in the United States presidential election of 1880.
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1880 Democratic National Convention [SEP] Introduction
Tilden, however, was ambiguous about his willingness to participate in another campaign, leading some delegates to defect to other candidates, while others stayed loyal to their old standard-bearer. As the convention opened, some delegates favored Bayard, a conservative Senator, and some others supported Hancock, a career soldier and Civil War hero. Still others flocked to men they saw as surrogates for Tilden, including Henry B. Payne of Ohio, an attorney and former representative, and Samuel J. Randall of Pennsylvania, the Speaker of the United States House of Representatives. The first round of balloting was inconclusive. Before the second round, Tilden's withdrawal from the campaign became known for certain and delegates flocked to Hancock, who was nominated.