Final answer:
Michelangelo's David, completed in 1504 and known for its classical representation of the Biblical hero and its embodiment of High Renaissance ideals, is regarded as the most valuable sculpture of the Renaissance period.
Step-by-step explanation:
When considering the most valuable sculpture made during the Renaissance, we look to the works that have had a profound impact on art history and that embody the ideals of the period. David by Michelangelo, completed in 1504, is often cited as one of the most iconic and valuable sculptures of the Renaissance. This monumental sculpture was originally intended for Florence Cathedral's roofline, but its exceptional beauty and portrayal of classical ideas such as contrapposto and ideal naturalism led it to be placed in the Palazzo Vecchio. Michelangelo's David differs in that it does not depict the slain Goliath at the hero's feet, focusing instead on David's tense and ready posture before battle, a singular example of the High Renaissance sculpture.
The Pieta by Michelangelo is another remarkable work from the High Renaissance showcasing classical beauty and idealism, but it is Michelangelo's David that remains the prime example of the period's sculpture. Donatello's David and Ghiberti's Gates of Paradise are also significant in their own right, representing pivotal shifts in artistic style and technique during the Renaissance. However, Michelangelo's David is often put forward as the most valuable due to its size, intricate workmanship, and its status as a symbol of Florentine freedom.