Former senator George Allen signs an autograph for a campaign volunteer in 2012 in Winchester, Va. Autographs demonstrate the enduring appeal of the signature as a mark of authenticity. (Katherine Frey/The Washington Post)
Adam Arenson is associate professor of history and director of the urban studies program at Manhattan College, and most recently the author of "Banking on Beauty: Millard Sheets and Midcentury Commercial Architecture in California."

It’s the end of an era: Major credit card companies announced last month that they will no longer require signatures at the point of purchase. All those squiggles on carbon copies, on paper and now on touch screens will soon become history.

But we don’t have to worry about the death of the signature quite yet. That’s because, unlike typewriters, cassettes, VCRs or any of the other relics of the pre-digital age, signatures still carry a certain cachet, a power we can attribute to their long history as marks of personal authenticity.

The signature can powerfully evoke the presence of a person, living or dead, famous or family. In the 19th century, people collected signatures, first snipping them from letters and then visiting notable people to ask for signatures in person. Soon collectors were seeking out the carte de visite, a postcard that displayed a likeness and a signature, a predecessor to the signed glossy photograph of the Hollywood era. It was the best way to remember a brush with greatness, short of obtaining a lock of hair or a death mask (not easy items to acquire).

And indeed, the signature has transformative powers. What may have been the first commercial use of signatures turned a notorious clunker into a household item: the Merriam-Webster dictionary.

In 1853, George and Charles Merriam bought the rights to Noah Webster’s 1828 “American Dictionary of the English Language,” a landmark work of scholarship filled with extensive (if often erroneous) etymologies and Webster’s distinctive spelling innovations. Some have stuck — color for colour — but others have not — “alternativ,” for example.

The product of decades of work, Webster’s dictionary was 1,500 pages long and carried an exorbitant price tag of $6 (more than $170 in today’s dollars). Webster had wanted to create a landmark dictionary, and 10 years after his death, he got his wish — but not on the basis of his spelling, his scholarship, or his Enlightenment and Federalist ideals, as he had intended. The Merriam brothers abridged the work, threw out many of Webster’s spelling choices and deployed patriotism — and signatures — to market their version as a national standard.

In the years that followed, the Merriams sent copies of their new edition to noted politicians and thinkers — and then they clipped the signatures from the courtesy thank-you letters they received and used them in advertising for the dictionary. Printed in different fonts of varying size, on pages bordered with complicated spiral and flower patterns, advertising pamphlets were filled with the wide, irregular signatures of Washington Irving, Ralph Waldo Emerson, Daniel Webster, Henry Clay, James K. Polk and Millard Fillmore, all quoted praising the dictionary and, by implication, endorsing it.

One pamphlet included the words of acknowledgment — not quite testimonials — from 15 state superintendents of education. Another advertised the support of “one hundred and four Members of Congress,” a claim that led detractors to question a congressman’s authority to judge linguistic matters.

The Merriams made Webster mean dictionary by using famous names — rendered authentic by their signatures — to sell the dictionary. Their trailblazing marketing made them enemies: Washington Irving, for one, remembered the cantankerous Noah Webster and complained that he did not wish to be seen as endorsing Webster just because he sent a thank-you letter.

Yet using signatures in advertising remained a common form of testimonial in the 20th century. With the advent of color printing, signatures were joined by smiling likenesses of celebrities and CEOs, conveying a guarantee about the quality of the product inside. While the legal power of the signature remained, the ubiquity of the celebrity signature — printed on cereal boxes, signed casually on hats and shirts and even skin — presaged the death of the credit-card receipt signature. As signatures abounded, their value dropped toward meaninglessness.

And yet signatures still matter. Documents signed by Abraham Lincoln — even mere receipts — fetch thousands at auction. And even the absence of a personal signature attests to its power: I have peered at the signed “X” on many government documents — the mark of a Native American on a treaty, an ex-slave on a deposition, a veteran on a pension claim — wondering at what we cannot know about them because the subjects were unable even to sign.

Nor is the signature going to disappear altogether. As we stop signing receipts, the signature will continue on business letters, on personal notes and as a prize for fans. There will still be the Donald Trump Signature Collection. So don’t worry.

Or do: Even if it continues to serve its legal purpose, the decline of our collective penmanship may make the signature just one unreadable squiggle among many.