One way to earn Glimmer quickly is to visit each planet and clean out all Region Chests. These are marked on the map as a cross with dot in the middle of it. Each one you open can give you some gear, but after reaching max Power level it's unlikely you'll find much value from that.
I believe the answer will be the medieval period
Alliteration is when the same sound shows up at the beginning of words that are close together. The lines that contain this are:
2. Wanders and watches with eager ears,
3. Till in the silence around him he hears
4. The muster of men at the barrack door,
