Short answers, pulled from the story.
Nicholas Hilliard (c. 1547 - before the 7th of January 1619) was an English goldsmith and miniature painter who served as limner to Elizabeth I and James I. He is regarded as "the central artistic figure of the Elizabethan age" and his small oval portrait miniatures remain the defining visual image of Elizabethan England.
Hilliard was born in Exeter in 1547. He apprenticed to Robert Brandon, the Queen's jeweller and city chamberlain of London, and was made a freeman of the Worshipful Company of Goldsmiths in 1569 after completing seven years of training.
The Art of Limning is a treatise on miniature painting written by Hilliard around 1600. It is preserved in the Bodleian Library and discusses technique, the importance of open light over shadow, and the challenge of capturing fleeting expressions in a portrait.
The largest collection of Hilliard's work is in the Victoria and Albert Museum in London. The National Portrait Gallery and the British Museum in London also hold several examples of his miniatures and related objects.
Yes. Hilliard endured financial troubles for forty-five years despite serving two monarchs. He lost money in a Scottish gold mine venture around 1574, was briefly imprisoned in Ludgate Prison in 1617 for standing surety for another man's debt, and in 1601 asked the Secretary of State for permission to leave London to live more cheaply.
Hilliard crafted jewelled lockets to hold portrait miniatures, worn around the neck as personal objects. Among the best known are the Armada Jewel, given by Elizabeth to Sir Thomas Heneage; the Drake Jewel, given to Sir Francis Drake; and the Lyte Jewel, now in the British Museum, which James I presented to Thomas Lyte in 1610.