Today in the history of the American comic strip: September 4

American cartoonists and writers may not have invented the comic strip, but some argue that the comics, as we know them today, are an American creation. Clearly, the United States has played an outsize role in the development of this underappreciated art form.

9.4.1882: Harold Knerr, who drew and wrote The Katzenjammer Kids for 35 years, is born in Bryn Mawr, Pennsylvania.

9.4.1942: Pruneface, one of the main villains in the Dick Tracy strip, makes his first appearance.
 
9.4.1951: Snoopy’s doghouse appears in Peanuts for the first time. The beagle made his initial appearance in 1950, the year the comic debuted.

9.4.2005: The appearance in Blondie of characters from other comic strips, which began July 10 to celebrate Blondie’s 75th anniversary, comes to an end.

9.4.2007: The Complete Terry and the Pirates, Vol. 1: 1934-1936, marks the start of a six-volume series from the Library of American Comics reprinting Milton Caniff’s strip.

9.4.2018: After a buildup that lasted more than two months, Walt Wallet of Gasoline Alley finally learns that the real reason he’s been invented to visit the Comics Retirement Home (senior housing for retired comic-strip characters) is to celebrate Gasoline Alley’s 100th birthday.

Most of the information listed here from one day to the next comes from two online sites -- Wikipedia, and Don Markstein's Toonopedia -- as well as 100 Years of American Newspaper Comics, edited by Maurice Horn. Note that my focus is on American newspaper comic strips (and the occasional foreign strip that gained popularity in the United States). Thus, comic books and exclusively online comics are not included here.