There's always more to be said, but I have two past answers on the tricorn that may be useful to you:

What was the purpose of the tricorne hat? It doesn’t seem like it would provide much protection from the sun or the elements. Was it sort of just a fashion item? (this is an extremely short answer for this sub, but ultimately there is no in-depth way to respond)

The tricorn hat seemed to have gone from being THE hat of the 18th century to almost disappearing over night in the 19th century. Was this a case of tricorns being "so last century?"