Anyone who knows about Magna Carta and King John has probably heard of Stephen Langton, the Archbishop of Canterbury who brokered peace between the king and his rebellious barons and made the Great Charter possible.
But Stephen Langton has a far greater claim to fame. We take advantage of his deep biblical learning every time we open our Bibles, because he was the one who came up with the chapter divisions we take for granted.
Before Langton (1150-1228), several people had tried to divide the longer books of the Bible into more manageable chunks. But his version was the one that stuck and is the basis of the chapters we use today.
The advantages of chapters are obvious. Apart from making it easier for students, they help us find our way through the text by identifying the different sections of a narrative and telling us where stories and themes begin and end. Not all Langton's chapter divisions work, which is why some Bibles lay out the text in a way that crosses the chapter heading. But what's surprising is that 800 years after he did his work, so many of them do.
What about the verse divisions? They came a lot later. Italian Dominican scholar Santi Pagnini (1470–1541) divided the New Testament into verses, but they were a lot longer than the ones we have today and didn't catch on. The credit for our system today goes to a French scholar, Robert Estienne (1503-59), also known as Robertus Stephanus (Estienne or Etienne is French for Stephen). He created a verse numbering system in his 1551 Greek New Testament and in his 1553 French Bible. The numbers were printed in the margins, but in 1555 he produced a Vulgate (in Latin) which integrated them into the text. Estienne was a learned man, but his working conditions were sometimes not ideal: on one occasion he divided the New Testament into verses as he rode from Paris to Lyons to meet a printer's deadline – in the rain.
The first English Bible to use chapters and verses as we have them today was the Geneva Bible in 1560. Almost all Bibles use them because of their convenience (though the popular translation The Message only has chapters.).
However, it's worth saying that no matter how useful they are, they can be misleading. They are human interpretations of the sacred text, and humans can get things wrong. One example is the story of Jesus meeting Nicodemus in John 3. The story actually begins in John 2:23-25, and ignoring this means we don't understand it as well as we should. Wise readers will be careful to pay attention not just to chapters and verses but what the text is actually saying.