Snakenborg,Marchioness of Northampton in1569
I recommend using silk cotton for replicating the garment.The portrait shows gold purl centres and gold couching on the stems and leaf outlines. The original painting can be seen at the Google art project http://www.googleartproject.com/en-gb/collection/tate-britain/artwork/a-young-lady-aged-21-possibly-helena-snakenborg-later-marchioness-of-northampton-british-school-16th-century/329300/