Lining: Process that consists in reinforcing the original fabric by the means of another one that is adhered to the back. Usually it is done when the old canvas has become too weak to withstand further ageing or whose damages are too severe and extensive to be remediated by local treatments like patching or tear mending.
In this case, the painting was seriously damaged when the hook that was holding it failed. On its way down, it hit a chair causing big tears that made the owner believe that the painting was beyond repair. Due to the extreme brittleness of the original support, a lining process was highly recommended.
Previous to the lining, all the deformations and planar distortions were treated with humidity and weights. After that, the threads were carefully realigned and the painting in the damaged areas consolidated, in order to obtain a perfectly flat surface. Finally, the lining process was done holding everything together again. Some filling and inpainting in the teared areas completely concealed the damages.