The Germanic peoples originally decorated their trees with fruit, candy, cookies, and flowers. These ornaments symbolized the abundance to come when the Sun shed His warmth.
While a lovely custom, the decorations were heavy and difficult to keep on the tree.
After a few years, the area glassblowers put their heads together and came up with a solution:
They could decorate trees with the lightweight glass orbs they produced.
The use of the orbs made tree decorating an easy process.
Even better, the round, three-dimensional shape of the ornaments replicated the shape of the Sun.
This provided Pagans with a simple way to honor, their own beliefs, in the now, Christian world.