 Complete the following phrase:  The city authorities had erected a new, attractive, and roomy building for the school, and now placed at its head Friedrich Fröbel, already widely known for his book The Education of Man 1826. Also present were Heinrich Langethal 17921879 and Wilhelm Middendorf 17931853 who had been associated with Fröbel for fourteen years in his school in the Thuringian village of Keilhau, and after the few years in Burgdorf were again to be his helpers when the first kindergarten was opened at Blankenburg, another Thuringian town. All three had been members of Lützows Free Corps during the 