In 1172, a wealthy Italian widow named Berta di Bernardo left 60 cents in her will to purchase stones and construct a bell tower. The construction began on August 9, 1173. The tower began to sink after the construction reached the third floor, in 1178. This was because the tower had a mere three-meter foundation, set in weak, unstable subsoil. Construction of the tower was halted for almost a hundred years, since the city-state of Pisa was engaged in wars with Florence, Genoa and Lucca.