This was the name of two ruling queens of Portugal. It was also borne by the Habsburg queen Maria Theresa (1717-1780), whose inheritance of the domains of her father, the Holy Roman emperor Charles VI, began the War of the Austrian Succession.
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 has been used in the English-speaking world since the Protestant Reformation. In America it received a boost in popularity after the birth of Esther Cleveland (1893-1980), the daughter of President Grover Cleveland [1].
In England, this Latin form has been used alongside the vernacular forms Ann and Anne since the late Middle Ages. Anna is currently the most common of these spellings in all English-speaking countries (since the 1970s), however the biblical form Hannah is presently more popular than all three.
The name was borne by several Russian royals, including an 18th-century empress of Russia. It is also the name of the main character in Leo Tolstoy's novel Anna Karenina (1877), about a married aristocrat who begins an ultimately tragic relationship with Count Vronsky.