Sensationalist journalism has a long and storied history. In the 1570s Book of Marytrs a story is told about a young girl who called God a “doting old fool.” When she was later sent to the market by her mother, she was instantaneously struck dead. Later that evening she was buried. Many other similar stories appeared in the 1800s to warn against a variety of sins.
The first successful “modern” tabloid was The New York Sun, started in 1833 by Benjamin Day. The Sun had a circulation of 20,000 readers and may have been the largest circulating daily paper up until that time.
Tabloid journalism evolved from that point forward, becoming Yellow Journalism in the time of Hearst and Pulitzer and being epitomized by Generoso Pope Jr. and the National Enquirer. Southern Nazarene University offers a fantastic timeline of the rise of tabloid journalism, broken up by decade, here.