There are a number of sources you can use to learn about Penn's history, including:

The Daily Pennsylvanian, Penn's student newspaper

Penn Libraries has digitized back issues of the Daily Pennsylvanian (1885-2002). 

Daily Pennsylvanian articles from 2001- present are available through the DP website. You can search for specific dates, headlines, writers, and more with the advanced search option.

The University Archives

The University Archives contains a wealth of primary source materials related to the history of the university. They've compiled a Penn History page that includes links to online exhibits, biographical information, and other materials.

The University of Pennsylvania Almanac, the journal of record, opinion, and news

The Almanac is a weekly publication primarily for staff and faculty at Penn. The Almanac contains calendars, policy statements, obituaries, position changes, speech transcripts, special reports, and other news articles. Back issues have been digitized from 1954 to the present.  The Almanac is an important repository of Penn's institutional history from the mid 20th century to the present.

Print and online materials in the Penn Libraries collections

You can also search within the University of Pennsylvania subject heading in the Franklin Library Catalog, to find materials located at the University Archives, the Van Pelt Library, the Rare Book and Manuscript Library, and elsewhere in the Penn Libraries.