Franchise mark "DIRECCIÓN GENERAL DE SEGURIDAD - SECRETARÍA GENERAL" on cover to Roquetes. Returned to sender with Roquetes arrival backstamp dated on December 8, 1937, and Barcelona re-entry of December 9, 1937.
Cover to Colonia de Niños, from Madrid to Alicante. Many children were moved from Madrid and other cities near the front to safer zones in the coast, where they were hosted in special colonies for children. Unreadable postmarks, but content inside dated on November 27, 1937. Very rare.
Postal stationery Edifil 69 uprated with 10c Edifil 682 with Madrid postmark "Sucursal Nº 9" dated on May 19, 1937. To José Luis Estrada Segalerva in Porlier prison, 3rd gallery. José Luis Estrada was sentenced to three years to forced labor for disaffection to the regime, by a sentence of February 20, 1937 issued by Madrid's Jurado de Urgencia Nr. 3.
Post card with franchise mark "XIII Cuerpo de Ejército / Jefatura de Sanidad" sent by a doctor in the Field Hospital of the XII Army Corps, Base Turia Nº 3, CC12. No postmarks, but text dated in Hellín on September 27, 1937.
Stationery post card Edifil 75 upgraded with two stamps 5c Edifil 681, from Valencia prison to Madrid, with Valencia postmark partially readable and text on the back dated on April 22, 1937. The sender is Luis Barrero, and he gives his sender info on the front: 4ª 472, wich is 4th Gallery, Cell 472.
Stationery post card Edifil 75 to the prisoner Joaquín Juncosa Molins, in Casa de Trabajo, Alcalá de Henares. No postmark, but text on the back dated in Madrid on January 2, 1937. Mark "CENSURADA" in blue and "BREVEDAD / EN LA CONTESTACIÓN".
Cover to Mollet del Vallès with very rare franchise mark "Columna Cultulra y Acción / Roja y Negra / Franqueo / AIT - CNT - FAI", Content dated on February 20, 1937 in Benastár, Huesca. The letter gives the sender's info: "Ejército Popular de Catalunya, Compañía Granollers".
Cover from Calanda, Teruel, to Mollet del Vallès, with mark "Grupo de transmisiones / y señales" used as censor, plus pencil note "Censura Guerra" and signature of the censor. Unreadable date on postmark, but content dated on September 11, 1937.
145 Brigada Mixta mark used as franchise on post card from Codo, Zaragoza, to Mollet del Vallès. Sender's info reads "145 Brigada Mixta, 4th Battallion, Gun Machine Company, Delegation in Alcañiz, Teruel". Text dated on October 23, 1937.
Milícies Antifeixistes de Catalunya field post card to Barcelona, with very rare mark used as franchise reading "División Francico Ascaso / Regimiento / Nº 1 / Durruti / 3º Batallón". No postmark, but text dated on June 13, 1937.
Cover with letterhead Socorro Rojo Internacional, Correspondencia del Combatiente from the front to Madrid, with postmark dated on June 26, 1937. Sent by the soldier Carlos Pascual, 28 Brigada, 2º Batallón, 4ª Compañía.
Air mail cover from the Madrid front to Gibraltar, with special field post postmark "FRENTE DE MADRID / CORREOS / 23 SET 1937 / ESTAFETA Nº 19" and Madrid censor mark Heller RM1.1.. Madrid air mail backstamp and mark "Via Marseille y Cerbére".