From the Mayflower History Website, http://www.mayflowerhistory.com by Caleb H. Johnson:
Isaac Allerton was about 34 years old when he came to Plymouth on the Mayflower in 1620. He had been a long-time member of the Pilgrims' church in Leiden, and was recorded as having been a tailor from London. He married his first wife, Marry Norris, in Leiden, in 1611, and there had children Bartholomew, Remember and Mary, all of whom came on the Mayflower with him. He and Mary buried a child, not yet named, at St. Peters on 5 February 1620. Isaac Allerton had a sister Sarah in Leiden, who married to Mayflower passenger Degory Priest. Mayflower passenger John Allerton, also a Leiden resident, most likely was a relative as well, although the exact relation has not been discovered.
Isaac Allerton was one of the more active and prominent members of early Plymouth. He was elected as Governor Bradford's assistant in 1621, and continued as an assistant into the 1630s. In 1627, he was sent to negotiate the Plymouth Colony's buyout of the Merchant Adventurers, the investors who had originally funded (and had hoped to profit from) the Colony. The Colony was about £2500 in debt; a small group of Plymouth's residents, including Bradford, Brewster, Standish, Fuller, and Allerton, sought to assume the debt themselves in return for the rights to profit from the company. Allerton was sent to England to negotiate further, and would return to England on several more occasions. Unfortunately for the others, Allerton began to use his "free" trips to England to engage in some private gains, purchasing goods and selling them in the Massachusetts Bay and Plymouth. He also used his capacity as Plymouth's designated negotiator to engage the Colony in a number of unapproved money-making schemes: he went so far as to purchase ships (which he partially used for his own private trading), and to attempt to negotiate grants and patents for trade--all at great cost to the company and none of it approved by the others back at Plymouth. When his trading schemes failed, the Company found itself in far greater debt than it ever started out with.
When Allerton's wife Fear died at Plymouth about 1634, and with the general ire of the Colony against him, he had little reason to stay. He moved to the New Haven Colony, and by 1644 had remarried to his third wife, Joanna Swinnerton. Isaac Allerton remained an active trader, and did regular business with the Dutch at New Netherland in modern-day New York. Records of his trading can be found in numerous other colonies as well, including Virginia and Barbados.
Will of Isaac Allerton, 19 October 1659
At a Court of Magistrates Octob. 19. 59
A writeing presented as the last will & Testament of Isaac Alerton, late of Newhaven deceased, wth an account of certaine debts, dew to him; & from him;
An account of Debts at the Duch
first, 700. & odd gilders from Tho: Hall by Arbitration of Captaine Willet, & Augustine Harman; about Captaine Scarlet wch I paid out,
And there is 900 gilders owing by John Peterson the Bore, as by Georg Woolseyes booke will appeare; & severall obligations thereto,
ffrom Richard Cloufe owes, as Georg Woolseyes Booke will make appeare; I thinke 900. gilders, but his Estate being broken. I Desire that what may be gotten may be layd hold on for mee,
Due from william Goulder 270, od gilders, by his Bill appeares;
Due from John Snedecare a shoomaker 150, od gilders as by his acco appeares.
from the widdow of the Hanc Hancson due as by severall Bills & accounts;
Peter Cornelioussen 120. od guilders as by ye account will appeare.
Due from Henry Brasser for rent for 28 moneths, from the first October 1656. to the last of May 58: for three roomes at 3 gilders a week. I am in his Debt for worke of the old acco wch must be Deducted;
there is 20 li in George Woolseyes hand, that came fro. mr Tho Maybue for mee
There is 420. oaf. gilders that I owe to Nicholas, the ffrenchman, & a Cooper I owe something to, wch I would have that 201; in Georg Woolseyes hand, & the rest of that in Henry Brassers hand to them two;
And now I leave my son Isaac Allerton and my wife, as Trustees to receive in my debts, & to pay what I owe, as farr as it will goe & what is overpluss I leave to my wife and my sonne Isaac, as far as they receive the Debts to pay what I owe;
In Captaine Willetts hand. a pcell of booke lace 1300 & odd. guilders Wch I left in trust with Captaine Willett to take care of: Seale
My brother Bruster owes mee foure score pounds & odd. as the obligations will appeare.
Besides all my Debts in Delloware Bay & in Virgenia wch in my booke will appeare, & in Barbadoes. what can be gott; Witness. Isaac Allerton Senior John Harriman
From: James Savage, Genealogical Dictionary of the First Settlers of New England:
Allerton, Isaac, one of the pilgr. in the Mayflower, at Plymouth, 1620, at one time the richest of the Co. was an Assist. 1621, the sole officer for three yr. under the Gov. He brot. w. Mary, three ch. Bartholomew, Remember, and Mary. His w. d. 5 Feb. after land. and he m. 1626, Fear, d. of Elder William Brewster, bywh. he had Isaac, H. C. 1650; and prob. no more. This w. d. 1633, and when he liv. at New Haven, 1646, he had third w. Joanna, wh. is honor. after d. of her h. as having giv. shelter to the regicides, Goffe and Whalley, tho. with the usual felicity of tradit. the merit was ascrib. to her gr.d. (then a small ch.) and liv. to 1684. As agent for the Co. he went to Eng. three or four times, but gave not satisfact. in the latter visit; and on his private business was oblig. to go, more than once, of all wh. large statem. is seen in the Hist. of Bradford. In 1643, the Dutch, with wh. he had passed some yrs. havinglost the coufid.of his early friends bef. 1631, would employ him, withUnderhil, to raise from the Eng. a force for their protect. against the Ind. but soon after he was sett. at New Haven, and there d. 1659, insolv. Largely he had speculat. at the Eastward and soon after dismiss. from the Plymouth agency, had a trading-house at Machias, destroy. 1633 by the French, met various disasters by shipwrecks of his fishing vessels, in prosecution of wh. business he sometime was engaged at Marblehead, and join. Salem ch. 1647; but seems almost always unlucky. His eldests. Bartholomew m. and liv. in Eng. as Bradford first taught us; Remember m. Moses Maverick of Salem; and Mary m. Elder Thomas Cushman, and d. 1699, the last surv. of the blessed band of the first ship, for wh. we may feel suffic. esteem without accept. the report of her being over 90 yrs. old. Sarah was the name of ten ascrib. to Maverick's w. and Young's Chronicles of the Pilgrims, Russell's Guide to Plymouth, the accos. of Judge Davis, in his Ed. of Morton's Memor. of Dr. Bacon in 3 Mass. Hist. Coll. VII. 243, and of Cushman in Geneal. Reg. VIII. 265-70, are all subject to no little correction since the contempo. Hist. of Bradford has been brot. to light.