In 1784, the Grand Duke Pietro Leopoldo established that all schools of art in Florence were to be combined in sole academy endowed with a gallery of antique paintings to permit the pupils of the Accademia delle Belle Arti to deepen their knowledge. The antique building, which once belonged to the hospital of Saint Matthew, was chosen and enlarged with adjacent space. This gallery has a number of paintings a collection of 15th- and 16th-century paintings and many 13th-16th-century Tuscan paintings, but they are all overshadowed by one massive sculpture - Michelangelo's David. It also has several of Michelangelo's unfinished Slaves sculptures. Michelangelo's David was in fact removed from Piazza Signoria where it had represented for over four centuries the strength and dignity of the Florentine Republic. In the early years of the 20th century, this statue was joined by other extraordinary works of art by the same artist, such as "St. Matthew" and the four "Prisoners" and finally by the "Pietà di Palestrina"