While in Castle Gohrde, Froebel talked with his friends about his favourite plan, which he had already had a view in Gottingen, of establishing a school for boys, and while developing his educational ideal to them and at the same time mentioning that he had passed his thirtieth birthday, and alluding to the postponement of his plan by the war, he exclaimed, to explain why he had taken up arms: 

“How can I train boys whose devotion I claim, unless I have proved by my own deeds how a man should show devotion to the general welfare?”

These words made a deep impression upon the two friends, and increased Middendorf’s enthusiastic reverence for the older comrade, whose experiences and ideas had opened a new world to him.

The Peace of Paris, and the enrolment of the Lutzow corps in the line, brought the trio back to Berlin to civil life.

There also each frequently sought the others, until, in the spring of 1817, Froebel resigned the permanent position in the Bureau of Mineralogy in order to establish his institute.

Middendorf had been bribed by the saying of his admired friend that he “had found the unity of life.”  It gave the young philosopher food for thought, and, because he felt that he had vainly sought this unity and was dissatisfied, he hoped to secure it through the society of the man who had become everything to him His wish was fulfilled, for as an educator he grew as it were into his own motto, “Lucid, genuine, and true to life.”

Middendorf gave up little when he followed Froebel.

The case was different with Langethal.  He had entered as a tutor the Bendemann household at Charlottenburg, where he found a second home.  He taught with brilliant success children richly gifted in mind and heart, whose love he won.  It was “a glorious family” which permitted him to share its rich social life, and in whose highly gifted circle he could be sure of finding warm sympathy in his intellectual interests.  Protected from all external anxieties, he had under their roof ample leisure for industrious labour and also for intercourse with his own friends.

In July, 1817, he passed the last examination with the greatest distinction, receiving the “very good,” rarely bestowed; and a brilliant career lay before him.

Directly after this success three pulpits were offered to him, but he accepted neither, because he longed for rest and quiet occupation.

The summons from Froebel to devote himself to his infant institute, where Langethal had placed his younger brother, also reached him.  The little school moved on St. John’s Day, 1817, from Griesheim to Keilhau, where the widow of Pastor Froebel had been offered a larger farm.  The place which she and her children’s teacher found was wonderfully adapted to Froebel’s purpose, and seemed to promise great advantages both to the pupils and to the institute.  There was much building and arranging to be accomplished, but means to do so were obtained, and the first pupil described very amusingly the entrance into the new home, the furnishing, the discovery of all the beauties and advantages which we found as an old possession in Keilhau, and the endeavour, so characteristic of Middendorf, to adapt even the less attractive points to his own poetic ideas.