text: It was 1360.. according to source.\n\nAlso, look at this time-line\n\nYear\n\n1173 Commencement of works on 9 August of the \n     year 1173. \n\n1182 Establishment of the "Opera Campanilis petrarum \n     Sancte Marie" (Stone Works of the bell tower of \n     Saint Mary). \n\n1185 Probable interruption at the height of the 4th \n     order. \n\n1198 The presence of a bell-ringer at the Tower is \n     documented - a sign that the building can hold \n     at least one bell, partially fulfilling the \n     purpose for which it was intended. \n\n1231 Building work, probably taken up again in the \n     first decades of the century, proceeds. A \n     workshop in which marble for the Tower is \n     worked is documented. \n\n1233 Oath of the worker Benato Bottici: in the \n     ceremony of investiture he pledges to be \n     "solicitous and attentive in the building \n     of the bell tower of the church, according \n     to the means of the Opera". \n\n1260 Giovanni di Simone, whose presence was \n     documented at the Opera del Duomo from 1260 \n     and, from 1267 as master builder, intervenes \n     in the construction of the Tower. Building \n     proceeds up to the seventh order, where a \n     correction of the axial inclination of the \n     building is made, which is no longer \n     rectilinear, having assumed a concave form. \n\n1278 Further suspension of building work. \n\n1292 Giovanni Pisano measures the inclination \n     of the Tower with a plumb line. \n\n1360 After almost a century of inactivity, \n     Tommaso Pisano completes the construction, \n     erecting the belfry and making the last \n     important geometric correction of the structure. \n\n-The End-