The belief that the universe as a whole is ageless and unchanging has largely prevailed in human thought since ancient times, with few notable exceptions, and even survived the Copernican and the Newtonian systems. In the 1920’s, the pioneering work of Georges Lemaître and Edwin Hubble set the foundations of evolutionary cosmology within the frame of General Relativity. Since then, the concept of cosmic age has entered the domain of physical science, opening up a rich and highly debated motif of modern cosmology. Today the age of the universe is estimated from a variety of independent observational probes. The most accurate measurement comes from recent observations of the cosmic microwave background by the Planck satellite, indicating a cosmic age of 13.8 billion years with an accuracy of ±0.2%. This result is consistent with independent lower limits from the age of the oldest known astrophysical objects, such as globular clusters, white dwarfs and low-metallicity stars.