The area of mathematics called "gauge field theory," though investigated in the nineteenth century, has only relatively recently been applied to problems in contemporary quantum mechanics.
Given:
Gauge field theory was investigated in the nineteenth century, but only recently has been applied to problems in quantum mechanics.
Differential geometry was investigated in the early nineteenth century, but only recently has been applied to the exploration of general relativity.
Evaluate:
The common relationship between these two examples is that some applications of a theory may not be initially apparent.