The search engine Google is showing this interactive animated Doodle on May 4th, 2015 for celebrating 360th Birthday of Bartolomeo Cristofori.
Cristofori was an Italian musical instrument maker credited with inventing the piano. One of his biggest innovations was creating a hammer mechanism that struck the strings on a keyboard to create sound. The use of a hammer made it possible to produce softer or louder sounds depending upon how light or hard a player pressed on the keys.
Cristofori was born on May 4, 1655 in Padua in the Republic of Venice
The total number of pianos built by Cristofori is unknown. Only three survive today, all dating from the 1720s.
The piano as built by Cristofori in the 1720s boasted almost all of the features of the modern instrument. It differed in being of very light construction, lacking a metal frame; this meant that it could not produce an especially loud tone. This continued to be the rule for pianos until around 1820, when iron bracing was first introduced.