August 12th, 1877
Thomas Edison patents the Phonogram

Noting that the sound of a telegraph tape transmitting at high speeds resembled spoken words, Edison developed a system using similar mechanics to record a telephone message and then play back the recording using a stylus on a tinfoil cylinder.

On 12th August, 1877, he recorded "Mary had a little lamb"- the first audio recording. It has been preserved, and can be downloaded from Project Gutenberg

This was the first time that sound had been recorded to be played back at a later time. Despite many advances in the various components, the principle behind the system of a needle running along a groove making a sound, which is then electrically amplified remains the same as that used in modern record players.

The phonogram was patented on 24th December, 1877.