Historical computers refer to early computing devices that laid the groundwork for modern technology. One of the first mechanical computers was the Antikythera mechanism, an ancient Greek device used to predict astronomical positions. Later, in the 19th century, Charles Babbage designed the Analytical Engine, which is considered a precursor to modern computers due to its use of algorithms and programmability. The 20th century saw the development of electronic computers, such as the ENIAC, which was one of the first general-purpose electronic digital computers. These early machines were large, expensive, and used vacuum tubes for processing. Over time, advancements in technology led to smaller, more efficient computers, paving the way for the devices we use today.