Robert belonged to an old Essex family of some wealth and substance. His father died before December 1380, and by the time he came of age (by November 1384) he had acquired, as heir to his father, his uncles and his brother, at least six manors and many other properties in the county. From his mother, who lived on another four years or so, he subsequently inherited Layer de la Haye, a manor she had acquired after the death of a former husband. In 1412 Tey’s landed holdings were estimated to be worth £93 6s.8d. a year, and this was probably an undervaluation.
Despite his evident closeness to Richard II, Tey somehow managed to keep on good terms with those of the affinity of the duke of Gloucester and the countess of Hereford throughout the 1390s and right up to Gloucester’s fall in the summer of 1397. For instance, he acted as a feoffee of the estates of the duke’s adherent, Walter, 4th Lord Fitzwalter, and he was party to important transactions on behalf of the countess’s retainer, William Marney.
During the period of transition after Bolingbroke seized power, Tey briefly held office as sheriff of Essex and Hertfordshire, and as such he is recorded holding elections to Henry IV’s first Parliament which met on 6 Oct. (his appointment being dated 30 Sept., the day an assembly of estates met to depose Richard II). He was confirmed as constable of Colchester in November (although removed from the shrievalty at the same time), and a month later he was appointed to a commission of array. Nevertheless, his royal annuity was not renewed, and there evidently remained suspicions about his allegiance to the new King. Indeed, in December 1400 he was put in the Tower. He may have owed his release (in time to be elected to the Parliament which assembled in January following) to his friendship with John Doreward, a member of the King’s Council. In August 1401 Tey was one of the four men summoned from Essex to attend a great council, and he received another such summons about two years later. Yet he was still not reconciled to the deposition of his former master: in 1404 when plots were uncovered in Essex for the overthrow of Henry IV and the re-instatement of Richard II (widely rumoured to be still alive), he was clearly suspected of being in league with the conspirators. On 16 Oct., when it was learned that he was intending to go overseas, he was ordered ‘upon his allegiance and under pain of forfeiture’ not to do so without a special licence authorized by the King personally; and a week later the castle at Colchester was put in the safeguard of the King’s son, Humphrey, never to be returned to Tey’s keeping. It may well be that Tey had been drawn into the plot by Maud de Vere, the dowager countess of Oxford and one of the principal conspirators, from whom he held land and near whose seat at Castle Hedingham his own estates were situated. On the other hand, perhaps he had done no more than allow certain of the less important rebels to escape from his custody at Colchester. Certainly, he was later fined £15 for the escapes of prisoners, which sum he was to be pardoned five years afterwards.
Tey was not appointed to royal commissions again for nearly seven years after his removal from the constableship. He may have owed his eventual rehabilitation and his reinstatement to the Essex bench in 1411 to the countess of Hereford, for, surprisingly enough, he remained on good terms with her and members of her circle throughout all his changes of fortune. Countess Joan and her councillors, Sir John Howard and Sir William Marney, acted as trustees of Tey’s manorial holdings, while he himself assisted Joan’s kinsman, Sir Richard Arundel, a ‘King’s knight’, to complete a conveyance of estates far away in Northumberland. In 1408 he was associated with the countess, her brother, Archbishop Arundel, and others of her affinity in the foundation of a chantry on Foulness, Essex, and he subsequently assisted her in making a grant of the manor of Margaret Roding to the Great Hall of Oxford university. In 1414 Marney named him as a feoffee of his property and as an executor of his will, and Tey later acted as an attorney and executor for Marney’s son, Sir Thomas (d.1421), as well. This friendship with Sir William led to connexions with the latter’s brothers-in-law, William Swinburne (who also asked him to be an executor) and Richard de Vere, earl of Oxford, on whose behalf he raised substantial loans on the security of manors in Essex and Buckinghamshire. Tey was evidently much in demand as a feoffee-to-uses, and among those for whom he appeared in this capacity were the lawyer Richard Baynard (a friend from his youth) and Baynard’s stepfather, the wealthy London draper, John Hende. Bartholomew, Lord Bourgchier, also considered him to be trustworthy when it came to dealings in property, and indeed after Bourgchier’s death Tey helped to put into effect his plans for the endowment of a college at Halstead.
Although after 1401 he never, apparently, sat in the Commons again, Tey showed a continuing interest in parliamentary matters by attending the Essex elections to the assemblies of 1407, 1411 (then standing surety for Sir William Coggeshall), and 1422. Meanwhile, in January 1420, his name had been included on the list sent by the local j.p.s to the Council as being among the knights and esquires considered best capable of military service in defence of the realm. Tey’s property in Colchester had always kept him concerned in the affairs of the town, and in 1415 he had been chosen by the burgesses to act as an arbiter in their dispute with the abbot of St. John’s. Among the others who looked to him for assistance in their transactions during his later years were Sir John Howard, Sir Andrew Butler and William Rookwood. Finally, on 1 Sept. 1426 his friend William Hanningfield named him as an executor of his will, leaving him as much as £30 for his trouble.