Chains appear as decorative elements in jewelry as well as practical applications (suspended oil lamps, scales, etc). Although the finished products look similar to Viking wire weaving, the method is different.

Chain for a small oil lamp. I took this at the traveling Pompeii exhibit when it was in Seattle.

Viking wire weaving bracelet
Wire weaving uses a single long wire, threaded back and forth, to create a strand.
Loop-in-loop (the Roman method) uses individual oblong rings. They are bent and hooked into each other. Here’s a modern tutorial.
Both types of chain finished by pulling them through a drawing plate. Going through the big hole first, then stepping down in size through the smaller holes, gives you a compressed and smoothed chain.
Using multiple loops, crossed and interwoven, creates a denser look, like this body chain from Pompeii. Search “loop in loop” on YouTube for many more tutorials.
Note: None of the work pictured above is mine. I’m looking forward to making some!