Who attempted to break up monopolies in the gilded age?

During the Gilded Age, prominent figures like President Theodore Roosevelt and his administration took significant steps to break up monopolies. Roosevelt is known for his vigorous enforcement of the Sherman Antitrust Act, targeting large corporations like the Northern Securities Company. Additionally, figures like progressive reformers and activists advocated for regulations to curb corporate power and promote competition. These efforts laid the groundwork for future antitrust legislation in the United States.