`df_search`

Full-text search over Diplomatarium Fennicum: 6,876 medieval charters, letters and account entries concerning Finland, 859–1530.

Parameters

parameter	type	default	notes
`keyword`	string	(required)	Search term, in the language of the documents and in period spelling. Swedish stemming and accent folding apply. Several words require all of them; `"quoted words"` require that exact phrase; a trailing `` is a prefix (`lepros`) and `\\|` lists alternatives (`reval\\|reual`).
`offset`	int ≥ 0	`0`	Pagination start.
`limit`	int 1–100	`25`	Results per page.
`language`	string	—	Exact, unaccented Finnish label: `ruotsi`, `latina`, `saksa`, `venaja`.
`issuingplace`	string	—	Case-insensitive substring of the place of issue — not the subject. Mixed vocabulary: historical Swedish for Finland and Sweden (`Åbo`, `Viborg`), modern elsewhere (`Tallinn` not `Reval`, `Gdansk` not `Danzig`). A third of the corpus records no place and is excluded.
`country`	string	—	Case-insensitive substring of the Finnish country label: `Suomi`, `Ruotsi`, `Italia`.
`year_min`	int	—	Earliest year the charter may fall in.
`year_max`	int	—	Latest year the charter may fall in.
`fuzzy`	int 0-2	`0`	Edit distance per term. `1` catches spelling variants — the usual reason a search looks thin. Pass a base form: a fuzzy term skips stemming. It is whole-word distance, so it does not reach inflections; a prefix does.
`match_all`	bool	`true`	Require every word. `false` matches any word — useful when a term may be spelled differently, but the total then counts charters matching only one word.
`research_context`	string	—	A sentence on what the user is researching. Not searched; written to the server log beside the query, so an operator can see what the corpus is asked for. ra-mcp's tools take the same parameter.

Query syntax

Several words must all appear. "Quoted words" must appear as that exact phrase.

A trailing * is a prefix: lepros* matches leprosi, leprosorum and leprosis. It needs at least 3 characters and expands to at most 300 forms (the most frequent; a capped search says so in a note). This is how to search Latin and German, which the Swedish stemmer never touches, and how to catch the spellings of a name. | separates alternatives within a term: bref|breff matches either, reval*|reual*|revel* any of the three prefixes. Alternatives are OR within the term and AND across terms, so lepros* reval*|reual*|revel*|reuel*|reffl* means "leprosy, and Reval in any spelling".

AND, OR and NOT are not operators — they are matched as ordinary words. Writing bref OR littera searches for or too, which on this corpus drags in 50 unrelated charters that happen to contain the word. To widen, drop a word or pass match_all=false.

This matters for the total as much as the results. With any-word matching, konung Stockholm reports 944 charters while only 77 contain both — BM25 still puts the good ones first (19 of the first 20 contained both terms), but the total is a claim about the whole result set.

How the filters behave

language is an exact match, because the labels are a closed vocabulary of 15 values — a substring match on latina would also sweep in the compounds latina, ruotsi and latina, venaja, which is a different question.

issuingplace and country are substring matches, case-insensitively, because the place vocabulary is open (499 values) and historical spellings vary.

issuingplace is the place of issue, which is a different question from what a charter is about. 2,314 charters (34%) record no place and are excluded whenever it is set, and a letter about Tallinn written in Åbo is issued at Åbo. DF 173 — the dean and chapter of Reval asking the bishop of Åbo to support their leper house, 1279 — has no recorded place and is unreachable through issuingplace="Tallinn" by any keyword. A filtered search therefore ends with a note saying so, and for the catalogue's modern names it gives the period forms to search in the text instead: Tallinn is reval*|reual*|revel*|reuel*|reffl*, Gdansk dantz*|dantsk*, Tartu darpt*|darbt*|dorpt*|tarbat*.

year_min / year_max test interval overlap: a charter is returned when its dating interval intersects [year_min, year_max]. Because 99.5% of charters have no end year, the interval used is a derived closed one — a charter dated 1347 with no end year is treated as [1347, 1347], not as extending indefinitely. Charters with no year at all (22 of them) are excluded from any year-bounded search.

An inverted range is rejected up front rather than returning a silent empty result.

Examples

df_search(keyword="konung")
df_search(keyword="konung", issuingplace="Åbo", year_min=1300, year_max=1400)
df_search(keyword="littera", language="latina", country="Italia")
df_search(keyword="\"de ecclesia\"")                       # exact phrase
df_search(keyword="lepros*")                                # prefix: leprosi, leprosorum, …
df_search(keyword="lepros* reval*|reual*|revel*|reuel*")   # leprosy AND Reval, any spelling
df_search(keyword="Perugia Lateranen", match_all=False)   # either word
df_search(keyword="Åbo", limit=50, offset=50)

Output

Diplomatarium Fennicum search results for 'konung': showing 2 of 277 records (offset 0)

**DF 2671** — 1446 — Stockholm, Ruotsi
  language: ruotsi · index term: Paikallishallinto, Asiakirjat
  (Konung Kristofer kallar marsken Karl Knutsson till fejd emot konung Erik på Gotland …

**DF 670** — 1357 — Åbo, Suomi
  language: latina · index term: Piispat, Asiakirjat
  (catalogued but not transcribed — no text available)

More results available. Use offset=25 to see the next page.

The total is a true count of matches, not the size of the current page.