Robert Stewart (1553-1593) was Earl of Orkney and Lord of Shetland. He was an illegitimate son of James V of Scotland and Euphemia Elphinstone (b. 1507), who was a daughter of the first Lord Elphinstone. He was therefore a half brother of Mary Queen of Scots. Nine mothers are known to have to have given birth to illegitimate children of James V of Scotland and Euphemia appears to have been little more than a passing fancy.
The rule of Earl Robert Stewart in Orkney was harsh and oppressive, although perhaps not to quite the degree of his son, Earl Patrick Stewart who succeeded him. He was overbearing and greedy for land, by whatever means.
Confirmation of his Bishopric rights in 1585 gave him absolute and legal control over the islands. He fell out of favour with James VI of Scotland who was investigating the land grabbing of the Sheriffs in general and Orkney's in particular. Earl Robert perhaps saw the light and began returning some of the lands that he has acquired by coercion to their rightful owners from 1587.
Patrick Bellenden was commissioned to fetch Earl Robert to Edinburgh but on arriving in Orkney with three armed ships, was opposed by Earl Robert in person leading a force of Orcadians who were still loyal to him. Patrick Bellenden was unable to collect the rents and skat, as instructed, and had to return to Edinburgh. Earl Robert remained in Orkney until he died in 1593.