Here are some key milestones:
* Early 19th Century: "The Adventures of Obadiah Oldbuck" (1827) is often cited as the first American comic strip. It used sequential panels with text to tell a story, but wasn't printed in a format we'd recognize today.
* Late 19th Century: "The Yellow Kid" (1895) was a popular comic strip published in newspapers. This is considered a major turning point, as it established the format of using a single panel with dialogue balloons for storytelling.
* Early 20th Century: "The Katzenjammer Kids" (1897) and "Buster Brown" (1902) were two early successful comic strips. They helped solidify the modern comic strip format.
* 1930s: The first "comic books" as we know them emerged in the United States, featuring a variety of stories and genres. "Famous Funnies" (1934) is often considered the first true comic book.
* 1938: The creation of Superman by Jerry Siegel and Joe Shuster marked the beginning of the superhero genre, which went on to become a cornerstone of comics.
So, depending on what you consider the defining characteristic of "comics," you could argue that they began in the early 19th century, late 19th century, early 20th century, or the 1930s.
Each period contributed significantly to the evolution of what we now know as the comic book medium.