Who is Robert Sidney, and what is his importance in the poem, To Penshurst?

Robert Sidney was Philip Sidney's younger brother, and at the time Jonson was writing, the lord of Penshurst. Robert Sidney was a notable statesman in the English court, as well as a patron for the arts. "To Penshurst" is written in praise of Robert Sidney and the rest of the Sidney family, who continued to be involved in English politics, art, and literature throughout the Elizabethan and Jacobean periods.