CRLF goes back a long way.
Systems based on ASCII or a compatible character set use either LF (Line feed, 10 in decimal) or CR (Carriage return, 13 in decimal) individually, or CR followed by LF (CR+LF). These characters are based on printer commands: The line feed instructed the printer to advance the paper one line, and a carriage return indicated that the printer carriage should return to the beginning of the current line. If the printer was only fed a line feed, it would advance one line and continue printing from that position on the next line (no carriage return was performed). It was also possible to cause a printer to overprint on the same line by using the carriage return since the print position would then be returned to the start of the line without advancing the paper - an action sometimes used on line printers to create bold text. Some of the other functions used with the line printers were things like VT for Vertical Tab (to move down some distance) and FF for Form Feed (go to the top of the next page).
Actually, the fact that a chr(10) (LF) is all that is needed on many sytems is sometimes annoying since technically it is only a line feed and the cursor should not go to the beginning of the next line without the chr(13) (CR). This can make it hard to format something where you just want to go to the next line but keep the cursor in the same position relative to the beginning of the line.
(And for anyone that doesn't know what a line printer is, they were commonly used on early computers and printed text a complete line at a time - at speeds of anywhere from 150 lines per minute to 2400 lines per minute and up - don't remember what the upper speed limit of these, 2400 was the fastest I ever worked with.)