Sentence:  The design, when finally developed, was a slight disappointment to Monsieur Deplis, who had suspected Icarus of being a fortress taken by Wallenstein in the Thirty Years' War, but he was more than satisfied with the execution of the work, which was acclaimed by all who had the privilege of seeing it as Pincini's <WSD>masterpiece</WSD>. 
Meaning of the word marked with <WSD> tags:  A piece of work that has been given much critical praise, especially one that is considered the greatest work of a person's career.