Man had developed in his knowledge that early engineering came about through the means of noticing the sun bouncing off of cliffs and discovering that that could be simulated through the sundial.
While there are many more other time developments between the sundial and the modern day watch, for the sake of convenience we are skipping over the less relevant ones.
The sundial is the first clock that we have solid evidence of.
King Roger's sundial in the palace is commemorated in all three, and it is to be noticed that the three inscriptions do not translate one another.
He taught, if he did not discover, the obliquity of the ecliptic, is said to have introduced into Greece the gnomon (for determining the solstices) and the sundial, and to have invented some kind of geographical map. But his reputation is due mainly to his work on nature, few words of which remain.