This embroidery (detail above, full piece below) is tucked away in a dark corner of the museum section of the Basilica di Sant'Ambrogio church in Milan. Neither Simon nor I photographed the label beside it so I can't tell you anything for sure about it. Even if I had the label information that would amount to a date and country of origin and no more. There is absolutely no information about this object on the internet that we can find (nor can Antoinette with her medievalist links).
So here is what I think: It is one of the most outstanding example of Gothic applied couched metal and filament silk thread work that I have ever seen, at least from a technical skill point of view. It dates from a period between 1400 and 1550, when the Italians were producing magnificent silk cloth and professional embroiders were employed to ornament it with bands or motifs stitched on linen and then applied like patches on lengths of fine silk cloth. It appears to be an altar cloth, featuring a number of saints in a stylised architectural setting. The detail is so fine that at first I thought the faces were painted. They are not. They are worked in the tiniest stitches in the finest silk. Who were the embroiderers? Difficult to say. They may have been Italian, but they might have been English, or even Flemish. They were probably women, but not necessarily. They might have been nuns, but more likely lay professional embroiderers.
I get the impression that whilst this piece is valued enough to be kept in the museum and displayed, there is so much gold in one form or another in Sant'Ambrogio that this embroidery is outshone in most people's minds by gold mosaics from the 5th and 13th centuries and the even more extra-ordinary 9th century golden altar (blog posts about the rest of Sant'Ambrogio's treasures to come...).