Frontinus quotes:

Inventions reached their limit long ago, and I see no hope for further development.

Laying aside also all considerations of works and engines of war, the invention of which has long since reached its limit, and for the improvement of which I see no further hope in the applied arts, I shall recognize the following types of stratagems connected with siege operations....

No greater care is required upon any works than upon such as are to withstand the action of water; for this reason, all parts of the work need to be done exactly according to the rules of the art which all workmen know, but few observe.

I will ignore all ideas for new works and engines of war, the invention of which has reached its limits and for whose improvement I see no further hope.