In this comprehensive work, even though Heywood as starting point takes French Revolution, even before that there has always been ideologies. In premodern societies religion played key role for workings of power. In the ancient times, especially in Roman times political culture consisted of bellatores (warriors), labratores (labourers) and oratores (philosophes and priests). Oratores played the role of the ideology.
In modern times, liberalism which promised liberty, fraternity and equality by means of reason and progress declared its victory in the person of French Revolution. A group of liberals who introduced themselves as ideologists suggested that under the guidance of reason and progress they would put an end to the superstition, servitude and reactionary. They were ardent supporters of the French Revolution. Through education it would be possible to spread emancipatory and egalitarian ideas of the revolution. However, after Napoleon had left the ideologists for the church and made a deal with them, he accused and humiliated this radical group by being ideologist in a pejorative way. What was improtant fro them was private property, individualism, freedom of consciouness and thought, tolerance and science.
The supporters of the ancién regime were against revolution and they were with the church, nobility and landed gentry, that's to say, aristocracy. Conservatives were pessimistic about human nature which was believed to be imperfect; they aspired a hierarchial, authoriterian, propertied, patriarchial and traditionalist society. E. Burke suggested that French Revolution materialized in accordance with some laws. He also wanted to find out these laws in order to prevent from happening new revolutions.
Although Marx shared the same belief in reason and progress with liberals to emancipate men, he disagreed with them in terms of ways and methods of materializing it. He thought that mind would not be able to provide man with emancipation and equality. For him, it is material conditions of life that determines the conscousness, consciousness can't determines life. Marx thought that the history of existing societies was the history of class struggle. Therefore, drinig force behind the development is not mind but class struggle. As the French Revolution thought, there was a cause behind all political and historical actions. Marx said that "All the philosophers have hitherto interpreted the world in various ways, however, the point is to change it."
Marx believed that ideology was "false conciousness" since via ideology working class looking at things not terms of their interests but in accordance with the eyes their rulers. It was a sort of curtain that prevent workers from seeing their real interests. In the German Ideology, he said that "dominant ideas of an epoch were the ideas of the ruling class". Therefore, the dominant thoughts were the ideas of the bourgeois. Both in terms of economic and political reasons, socialism was a reaction against liberalism and capitalism.
Since ideologies in different contexts take different from, they always tend to change and have new meanings. Contemporary ideologies such as conservativism, liberalism, socialism and anarchism don't have the same attributes with their perceptions of 19'th century. Also the same ideology is conceived in different manners and ways. Therefore, ideologies aren't fixed.