He was born in circa 1549, the son of Giles Jacob, citizen and merchant, of London. Giles Jacob died in 1580-1, probate being granted to his will on 16th March of that year. He was a member of the Merchant Taylors' Guild in the City of London. He had issue:

1 Robert Jacob
2 Thomas Jacob
3 Gisbright Jacob, of Clare Hall, Cambridge, dsp 1598.
4 William Jacob
5 Giles Jacob, leatherseller, of London, born in the parish of St Mary Colechurch; dsp, will proved 30th January 1593-4.
6 Jane Jacob, who married 1stly ----- Whitefoote, and 2ndly ----- Peers.
7 Anne, who died in 1585-6.

Robert matriculated at Trinity Hall, Cambridge, in 1570; MA 1573. He became a physician in 1579, specialising in Gynaecology and Obstetrics. He became a fellow of Trinity Hall, Cambridge, at the insistence of Queen Elizabeth I on 15th April 1586. His will was dated 16th March 1586-6, probate being granted on 5th June 1588.

In January 1583 the Russian ambassador wrote to Queen Elizabeth:

...We do glorify etc.... He has commanded to be declared to you that as touching the letters which you wrote to him by our English Doctor, Doctor Robert, and concerning those which he wrote heretofore to you, that you would for his health's sake send him a doctor, a learned man, and you, showing your good will towards him, have disappointed yourself, and sent him, of the doctors of your house, one that is a learned doctor and well experienced man in physic, Robert, a true and faithful learned doctor. And that you wrote to him that he would receive him and such as came with him, and give them good entertainment; and in so doing you have shown him your good will in sending your doctor to him. And he has entertained your doctor and the people that came with him, and has gratified them with his liberal goodness, and will place them accordingly to their worthiness (Calendar of State Papers - Foreign).

In 1584 a report from Sir Jerome Bowes on his embassy to Queen Elizabeth states.....the next day Dr Jacob, telling Shalkow in how ill a part I took my entertainment the day before, was answered "Let him thank God. God was his good God; for had he not come to the Emporer when even he did, he (would) have been torn to pieces and thrown over the walls" (ibid).

Whilst in Russia he did not involve himself in trade, the merchants of Muscovy having the monopoly. However, when his service was ended, he did bring back to England significant merchandise. This was impounded and he petitioned Walsingham for its recovery.. Apparently 10000 lbs of wax which he had shipped back was taken by the merchants in England, presumably London, which they took for her Majesty's use, which they were meant to supply her, and they also seized the rest of his goods, maintaining that they were forfeit, as having been brought over without license of the company, although Robert maintained that their Governor, alderman Banes, had indeed given him license to bring back on his return any such goods as he could earn in the Emporer's service. He prays for his goods to be restored. and that he may quietly enjoy these.. 'what with the death of my own dear brother, and with continued hazard to his own life in that country'...(ibid).


Reverend Charles J Robinson: A Register of scholars admitted into Merchant Taylors' from 1562-1874, Vol I, page 64.