Why was the restoration period named the way it was? What was restored?

The term "restoration" is derived from Charles II's coronation, which marked the return of the old English monarchical system of government after a brief period of republican administration.

the  wilmot proviso  was designed to eliminate  slavery  within the  landacquired as a result of the mexican war (1846-48). fearing the addition of a pro-slave territory, pennsylvania congressman david  wilmot proposedhis amendment to the bill.

this question shoud be under spanish category, not