Robert came from a prosperous local family, being the 3rd son of John "Wynn" ap Maredudd, and entered the service of first Sir Walter Stonor and then Sir Philip Hoby, both administrators and senior officials to King Henry VIII. Robert fought and was injured at the Siege of Boulogne in 1544, took part in the King's Scottish campaigns and traveled extensively across Europe. He invested in land across North Wales and married his first wife, Dorothy Griffith, a member of the local gentry, in 1570. Robert now needed a suitable family house and chose Conwy, a prosperous town that was known in the 16th century for its gentile society. He built the house of Plas Mawr there between 1576 and 1585.