Answer: Shift

The modern computer keyboard, created in the 20th century and scarcely changed since, is an electro-mechanical descendant of the typewriters that preceded it in the 19th century. While many of the keys on the keyboards we use today are specific to a digital work environment (like the “print screen” button that originally printed what was visible on the screen and now “prints” the screen to an image file), one particular key you might assume was a modern one traces its roots all the way back to 1878: the shift key.

Today, when you press the shift key, the key functions as a temporary modifier that shifts the case of letter keys from lower to upper case, number keys from the number to the associated symbol, and otherwise acts as a modifier—all functions being handled by the software drivers for your keyboard. When the shift key was introduced in 1878 with the release of the Remington No. 2 typewriter, the shift key was a mechanical key that literally shifted the inside of the typewriter to achieve a change in letter case.

When you pressed the shift key (depending on the model of typewriter), one of two things happened. Either the typebar basket, where the actual metal letters were held, shifted and aligned the upper case letters with the ribbon (in which case the typewriter was referred to as a “basket shift” model) or the paper-holding carriage and ribbon shifted to align with the upper case letters on the typebars (in which case the model was referred to as a “carriage shift” typewriter).

The introduction of the shift key revolutionized the typewriter industry as it greatly simplified the construction of typewriters which, prior to the shift key, had two complete keyboards (one above the other) to accommodate both lower and upper case letters.