Liberalism and progressivism within Islam or simply Islamic liberalism or Islamic progressivism are a range of interpretation of Islamic understanding and practice, it is a religiously left-leaning view, similar to Christian and other religious progressivism. Some Muslims have created a considerable body of progressive interpretation of Islamic understanding and practice. Their work is sometimes characterized as progressive or liberal Islam. Some scholars, such as Omid Safi, differentiate between "progressive Muslims" versus "liberal advocates of Islam". Liberal Islam originally emerged from the Islamic revivalist movement of the 18th–19th centuries. Leftist ideas are considered controversial by some traditional fundamentalist Muslims, who criticize liberal Muslims on the grounds of being too Western and/or rationalistic.