The query of which was the earliest computer is a difficult one. The very description of what a computer is has changed over the years and it is therefore unfeasible to definitively answer the question. Many devices once called "computers" would no longer qualify as such by today's standards.
Originally, the term "computer" referred to a person who performed arithmetical calculations often with the aid of an automatic calculating device. Examples of early mechanical computing devices included the abacus, the slide rule and arguably the astrolabe and the Antikythera device. The end of the middle Ages saw a reinvigoration of European mathematics and engineering, and Wilhelm Sticker’s 1623 device was the first of a number of powered calculators constructed by European engineers. In 1837, Charles Babbage was the first to conceptualize and plan a fully programmable mechanical computer that he called "The Analytical Engine". Due to limits of finances, and an inability to resist tinkering with the design, Babbage never really built his Analytical Engine.