This is the tamnan proper — the foundation-legend in its purest form: the sacred history of a relic, a stūpa or a city, the story a place tells about how it came to be holy. At 328 witnesses it sits between the larger Buddhist Chronicle and the smaller Secular History, and its content is overwhelmingly the braḥ dhātu (relic) and mīöṅ (city) legends: tamnan of the relic at Lamphun, of Chiang Saen, of Haripuñjaya, of the founding of Chiang Mai.
The most striking feature of this sub-genre is not its content but its uniformity as a batch, which points to a single documentary source rather than a natural cluster. Three signals line up too neatly to be coincidence:
Together these mark the Tamnan sub-genre as very likely a discrete digitized corpus folded into the catalogue — a different project's cataloguing conventions carried in with its records. That is a provenance fact, not a content fact, and it matters: counts and comparisons across this sub-genre should be read as "one source's holdings," not as an independent regional sample.
Almost entirely palm-leaf (327 of 328) and Tham Lanna, dated across 1760–1981. Beyond the Chiang Mai concentration it reaches Phrae, Lampang, Lamphun and — unusually — Bangkok (21), consistent with a scholarly collection that gathered witnesses centrally.