This piece is in pieces. Originally a cushion, the front and back have been separated and are displayed as separate items. The front shows a biblical scene in long-armed cross-stitch, while the back is decorated with the brick-stitch pattern shown. For completeness sake I will provide details on both pieces. In addition, there is a very similar piece preserved at the Kunstgewerbemuseum in the Kulturforum in Berlin. See http://www.doctorbeer.com/joyce/emb/westcush/westcush.htm for details. Another, similar design can be seen in Pattern Y-023

Description: "Altar cushion, German, late 14th century. Colored silks on linen"
Origin: Germany
Period: 14th-15th century
Current location: Victoria & Albert Museum, London, England
Museum number (front): 1324-1864
Object number (front): O84955
Museum number (back): 1324A-1864
Object number (back): O318615

Current Museum page:
Front: https://collections.vam.ac.uk/item/O84955/book-cushion-cover-unknown/
Back: http://collections.vam.ac.uk/item/O318615/book-cushion/

Current Museum Raw Record:
Front: http://www.vam.ac.uk/api/json/museumobject/O84955
Back: http://www.vam.ac.uk/api/json/museumobject/O318615

Original catalog description:
"Cushion Cover (upon which was laid the missal at the altar during celebration of the mass), of canvas embroidered with coloured silks in cross-stitch, and figured with a twisted column canopy, beneath which is the Virgin seated and child, with standing figure of St. Joseph bearing a basket in one hand and a lily in the other. This central group is flanked on each side by two angels. The back (No. 1324a) of similar work is figured with a diaper pattern of repeated octagonal panels containing two birds with tree between them and a symmetrically-arranged flowering plant. German. Late 13th centy. 19 in. by 13 in." (Cole: 315)

Personal Observations:

Fabric count: 28 Count fabric (Based on personal observation)

Colors noted (Matched under natural light to a DMC sample card):
    White Silk (DMC 746 )
    Green Silk (DMC 320)
    Red Silk (DMC 304)
    Brown Silk (badly faded)

References:
Cole, Alan S. A Descriptive Catalogue of the Collections of Tapestry and Embroidery in the South Kensington Museum. London: Printed by Eyre and Spottiswoode for H.M. Stationery Off., 1888.{https://books.google.com/books?id=KRktAAAAYAAJ}
 
Images:
Front:
http://media.vam.ac.uk/media/thira/collection_images/2006AV/2006AV2708.jpg
http://media.vam.ac.uk/media/thira/collection_images/2011FB/2011FB1135.jpg

Back:
http://media.vam.ac.uk/media/thira/collection_images/2011FD/2011FD8118.jpg

Patterns:
http://wymarc.com/images/patterns/pdf/Y010A.pdf