Hilliard painted miniature portraits. Painting miniatures is called limning and he was a limner. These miniatures were private pieces of art meant to be kept in secret by the commissioner.
There is a young man standing among roses. His identity has been debated, but he is commonly referred to as the Earl of Essex. This tiny portrait came from Warwick Castle, and was in the collection of Fulke Greville who was a friend of Essex. The Earl of Essex, at that time, was 22 years old and an ally to Queen Elizabeth I. Whether he was more than a friend is unknown, but it is known that the Earl of Essex stood by the Queen in hardships. One can assume that this young man is of great wealth and social stature because of his clothing and stance. Judging by the colors and style of the young man's dress, not to mention his hair style, we can assume he was of wealth. The black and white of his clothing were favorites of the Queen, and could signify his faith in her, or her's in him.
There is a latin phrase on the top of the portrait. It reads "Dat poenas laudata fides" or "my faith, though praises, brings suffering." This could signify how Essex felt about his relationship with the Queen. He has his hand placed on his heart, and that position is classically a position of love. However, it is argued that the hand on the heart is devotion and not love. The quote would have been well-known in miniature-owning circles at that time.
You will be more than welcome.