Froebel — where it appears
Named by 3 essays across one field — each of them below, with the objects they name alongside it.
The kindergarten was a geometry class
Froebel put paper folding into mass education in the 1830s, and did it as mathematics rather than as craft. His three categories — the folds of life, of beauty, and of knowledge — are the first systematic treatment of folding anybody wrote down, and the third one is a geometry syllabus.
Two traditions and a merge
Ceremonial wrapping, recreational folding and the kindergarten syllabus are three separate lineages with three separate purposes, and they were independent until the late nineteenth century. Told as one continuous tradition, the oldest date in any of them becomes the age of all three.
When two of them are first attested together
Every single date in this field is argued about by centuries, and a pairwise one is not. The earliest year at which two claims are both attested is simply the later of their two surviving sources, so it inherits the better-attested half of each pair rather than the worse — and the year at which all five lineages of practice are jointly on the record is 1838, one year from where the same claims are popularly dated together.
Named alongside it
The objects these essays reach for when they reach for this one.
AttestationDocumentary recordNoshiPajaritaCeremonial wrappingConstructive proofExact divisionFujimoto's methodPedagogyPrimary source