The Treaty of Dover was signed in 1670 between England and France, specifically between King Charles II of England and King Louis XIV of France. This agreement aimed to strengthen their alliance against the Dutch Republic and included provisions for military support and financial assistance. Additionally, the treaty contained a secret clause in which Charles II agreed to convert to Catholicism in exchange for French support. This aspect of the treaty was controversial and contributed to tensions in England, as many were wary of Catholic influence in a predominantly Protestant nation.