There is much less information on the internet about Karl than there is about his older brother, Julius. When he is mentioned in the Froebel literature, it is usually in the context of the Prussian suppression of the kindergarten in 1851 for which he is often blamed.
An alternative view is that the kindergarten was proscribed because of its association with radical feminist movements.
While in Zurich, where he opened a school, he met the prominent anarchist, Michael Bakunin in 1843. Highlighting this is not to suggest guilt by association but that like his brother, Karl moved in radical democratic circles.
Further evidence for this is to be found in the papers of Friedrich Hecker (1811-1881) 'a cult figure on the German Left' who went to the US in 1849, and who corresponded with both Karl and Julius Froebel.
One of the teachers at the school was Friedrich [von] Beust. In 1848 he was delegate from the Cologne Workers' Association to the Second Democratic Congress held in Berlin. At the Congress he spoke in favour of the "Demands of the Communist Party in Germany" which were written by Karl Marx and Frederick Engels. This was the political programme of the Communist League in the revolution that broke out in Germany. Friedrich Beust later became a member of the First International which joined in 1866, two years after Karl Marx, its most historically significant member.
Karl Froebel's support for the education of women led to his being engaged as the Rector of the Hamburg women's college (Hamburger Hochschule für das weibliche Geschlecht) in 1850 during the revolutionary period. His wife, Johanna Küstner Froebel, also played a prominent role in the college but it was closed by its founders in 1852 in the face of opposition and hostility towards it.
The college was founded by women of the German Catholic Movement which was started by the Silesian priest and revolutionary, Johannes Ronge. Together with his wife Bertha, Ronge founded the first kindergarten in England in 1854 and they wrote the popular exposition, A Practical Guide to the English Kindergarten.
The rise of feminism in Germany during the revolutionary period is discussed in this extract from a book by Ute Frevert which also briefly mentions Karl Froebel's role in the women's college.
Karl Froebel died in Edinburgh where he had opened a kindergarten. In 1875 , he had published in London a book entitled, Explanation of the kindergarten the subtitle of which reads, 'for those who are not satisfied with the present results of education, and search for principles which promise social improvement'. As this subtitle signals, Karl Froebel's book conceives the kindergarten - which he anglicised as 'play-school'- as an instrument of social emancipation and provides a politics of the kindergarten. As such, it is a most unusual contribution to the generally apolitical Froebelian literature. Among the pupils at Karl Froebel's Edinburgh school in 1897 was Clementine Hozier (1855-1977) who later in 1908 became the wife of the British politician, war-time leader and Prime Minister, Winston Churchill. Here an extract from her papers describing the school may be seen. Her account closely parallels that which later appeared in her daughter's biography of her . The schools was here in Moray Place in Edinburgh's New Town.
The Ronge's text and that of Karl Froebel are both reprinted
in:
Froebel, F. and K. Brehony (2001). Evolution of English nursery education. London, Routledge. Vol 6