Gibbon sat and listened unobserved to their strictures.
I walked about the outside, at first unobserved from within, the window was so deep and high.
The Franciscans slipped away unobserved, but Savonarola raising the host attempted to lead.
Like an Avon notice on a doorknob, the tracks in the mud were proof of an unobserved visit.
There must be countless indications of the course of Providence, for the most part unobserved, the meaning of only a few having become known to men.