The guitar was developed to replace the more unwieldy" lute which by the late Renaissance had grown to over a dozen courses in some cases. The guitar was considered a "proper" instrument to accompany a lady's voice, and "simpler" for a lady to manipulate. Baroque (@1600-1750) guitars are much smaller then even our parlor guitars and similar in construction to the lute. There are even a few guitars around that were built by Stratavarius, though none are playable. The guitar was meant to be an simple instrument, but within a few years composers were creating challenging music for it. Diabelli--Beethoven's own publisher--wrote some beautiful pieces for the guitar. This is also the time of the great flowering of Spanish composers such as Ferdinand Sor.

So, except for a few arias, I don't know of any "classical" songs written especially for the voice and guitar. This practice--as far as I know--stopped with the demise of the lute, about 1650. An 1890's revival, sheet music from that period would suggest that the ukelele was the instrument of choice, but I am over my head here.