DEKEN, Agatha ('Aagje') (1741-1804). Letter to Maartje (Agge) Kool. Amsterdam, June 27th 1774. Ms. on paper, paginated 1-21 in the outer upper corners. Signed at end. 4°. Cont. marbled wrps. -- Loosely added: a silhouette portrait in black ink and grey wash of Deken or Kool (?). (Outer margin warped, but in fine condition).Maartje Agge Kool (1752-1805) was the daughter of Agge Kool (1714-1789) and Trijntje Jansd. Honig (1717-1781) who were friends of Bettje Wolff and Aagje Deken. She was a member of the Mennonite Church, as were Wolff and Deken, and this letter by Deken deals with Maartje's conversion to the Mennonite faith. Written in a legible hand.