Anastasia was a French illuminator

Illuminated manuscript

An illuminated manuscript is a manuscript in which the text is supplemented by the addition of decoration, such as decorated initials, borders and miniature illustrations...

 of manuscript

Manuscript

A manuscript or handwrite is written information that has been manually created by someone or some people, such as a hand-written letter, as opposed to being printed or reproduced some other way...

s, apparently specializing in the elaborate decorative borders that were increasingly fashionable, and landscape backgrounds. By her day most manuscripts were produced in commercial workshops, and many artists were women, probably especially those specializing in borders, which were often produced by a different artist from the main miniature image. The School of Paris

School of Paris

School of Paris refers to two distinct groups of artists — a group of medieval manuscript illuminators, and a group of non-French artists working in Paris before World War I...

 was still the leading centre of illumination at this period, and Parisian works were widely distributed across Europe.

Nothing is known about her except for the praise heaped upon her by the medieval writer Christine de Pisan in her work, The Book of the City of Ladies (1405). Pisan describes her as the finest illuminator of her day, in her field.

”I know a woman today, named Anastasia, who is so learned and skilled in painting manuscript borders and miniature backgrounds that one cannot find an artisan in all the city of Paris-where the best in the world are found-who can surpass her, nor who can paint flowers and details as delicately as she does, nor whose work is more highly esteemed, no matter how rich or precious the book is. People cannot stop talking about her. And I know this from experience, for she has executed several things for me, which stand out among the ornamental borders of the great masters. (City of Ladies 85)