As an English name, Caleb came into use after the Protestant Reformation. It was common among the Puritans, who introduced it to America in the 17th century.
The name was originally used among early Christians in honour of the saint, as opposed to the classical character. In England it was commonly spelled Ellen during the Middle Ages, and the spelling Helen was not regularly used until after the Renaissance. A famous bearer was Helen Keller (1880-1968), an American author and lecturer who was both blind and deaf.
This name was initially more common among Eastern Christians in the Byzantine Empire, but it flourished in Western Europe after the First Crusade. In England it became extremely popular, typically being the most common male name from the 13th to the 20th century (but sometimes outpaced by William). During the later Middle Ages it was given to approximately a fifth of all English boys. In the United States it was the most common name for boys until 1923.
The name (in various spellings) has been borne by 21 popes and eight Byzantine emperors, as well as rulers of England, France, Sweden, Denmark, Poland, Portugal, Bulgaria, Russia and Hungary. It was also borne by the poet John Milton (1608-1674), philosopher John Locke (1632-1704), American founding father and president John Adams (1735-1826), and poet John Keats (1795-1821). Famous bearers of the 20th century include author John Steinbeck (1902-1968), assassinated American president John F. Kennedy (1917-1963), and musician John Lennon (1940-1980).
The forms Ian (Scottish), Sean (Irish) and Evan (Welsh) have also been frequently used in the English-speaking world, as has the medieval diminutive Jack.
In England and elsewhere in Europe during the Middle Ages this name was used in honour of the saint. However, it was not generally given in Ireland before the 17th century because it was considered too sacred for everyday use. It has since become very common there.