The first telescopes were refracting telescopes ... a tube
with lenses at both ends. The quality of the image depends
on the quality of both lenses, because the light must pass
through both of them.
The reflecting telescope was an improvement, because the
light doesn't have to go through the mirror. The quality of the
primary mirror only depends on the shape and shinyness of
its surface.
If you could carve an optically perfect parabolic surface out of
a piece of wood and coat it with a thin layer of shiny silver, then
you could use a log to make a good reflecting telescope.
II seem to recall that Newton made one out of brass !
