Text messages used to be limited in size to IIRC 140 characters. (And I still have that limit on my Garmin inReach--about an abysmal a texting device as you can get, but it works off Iridium, not the cell net. I can be on the back side of nowhere and still talk to emergency services.)

SMS is limited to 140 characters, but there has been a standard to send multiple messages in a row and have the receiving phone concatenate them automatically since about the year 2000. For older devices that that don't support it, they will get multiple messages and just show it as "(1/2)" etc (I had a Panasonic phone that didn't support it during the transition so I remember it well)