John "I am not from Denmark" Foss and his only wife Mary Berry
The genealogy of the John Foss Family is an internet mess, and I hesitate to enter the fray but, he is in the family so I will try to sort out what is documented about him and what is not. I know that I haven't been great at documenting my own sources, other than listing them at the bottom of the page, so I will try to do a better job with this one, especially in light of all the errors out there.
Two John Foss'
The two biggest reasons for all the mixups are the fact that there were two men, contemporaries, named John Foss who lived within spitting distance of each other, and a genealogy of the Foss family compiled and published by Guy S. Rix. The two John's are John Foss(t) of Dover and John Foss of Rye. Both men were married to women named Mary. Guy Rix combined the two men, added some fake Danish ancestors gave it all a good stir and left us with a Foss fiasco. Now some people really really want the Danish Ancestry to be true, but from what I have read David L. Foss had twins born in 1638, both girls. Rix substituted "Johan" for one of the girls names and Voila Danish Royalty added to the family. As always, if you think that I have any of the following information wrong, please point it out, and please include your documented sources. So here is what I can piece together about John Foss of Rye and John Fost of Dover.
In his will written 17 Dec 1699, John Fost of Dover names the following people: his wife Elizabeth and children; Humphrey, William, Mary, Jeminah, Elizabeth, and Samuel. He also names a son in law, James Warren. the inventory of the will was taken on January 8th. In his will he says the two youngest of his children are not yet of age. Presumably he named the children in their birth order and the youngest two would be Elizabeth and Samuel. New Hampshire Probate Records, Volume 3, page 161
In another probate record, that of James Goss (Goffe) the inventory of his estate is done and is now in the hands of John Foste who married the relict (widow) this was done on May 7 1688. witnesses are Humphrey Chadbourne and Richard Paine. Probate Records of the Province of New Hampshire, Vol 31 p. 320. So we know that the wife named in John Fost's will was Elizabeth Goss, widow of James Goss. She is not, however, the mother of all of his children. In The Collection of the Dover Historical Society, Vol 1, Births and Marriages, page 40, are found the following births: William Fost, son of John and Mary born March 11th 1673. Mary Fost, the daughter of William and his wife Mary, born June 24 1728 and Chadbourne Fost, son of William and his wife Mary born March 26 1731. The first wife of John Fost was Mary Chadbourne. Genealogical and Personal Memoirs Relating to the Families of the State of Massachusetts, Cutter and Adams.Vol 4 p. 2461. In his will proved 13 September 1667 Humphrey Chadborne of Kittery Maine left 5 pounds to his "cosson Mary Fosse". Kittery Town Book. Mary is said to be the grandchild of William and Elizabeth Chadborne.
At a town meeting held March 1, 1666 Thomas Edgerly, James Coffin, John Chirch, John Fost and others were recieved into the Town of Dover. Dover Town Records. He is on the tax roll of Cochecho that year. At a training the 21st of June 1669 John Fost and other men took the Oath of Fidelity. He is said to have been a tailor and attorney.
John Foss of Rye
There is a story, with slight variations, told about the arrival of John Foss of Rye. It is said that he was a Midshipman or caulker, on a British Man-of-War that was anchored in Boston Harbor. John absconded from the ship and made his way to Rye. I tend to believe that he was a caulker rather than a midshipman. Although no one knows exactly when he arrived, you can pin him down a bit based on information in town records and deeds.
John in the records
At the June court of 1662 quite a number of men were "presented" at court for various misdeeds involving alcohol including Francis Gray, of Great Island, who was presented for excessive drinking and disturbing the peace. One of the witnesses was John Foss. He took the oath of fidelity with others on 2 October 1666 at an election of military officers. Provincial Records of New Hampshire, Vol 40.
At a Porthsmouth town meeting in 1663 a highway was to be laid out from Nathaniel Drake's to Sander's Point which was where John Foss lived. Nathaniel Drake was by then married to Mary Berry Foss' mother.
At an Oct 1671 meeting he was paid 100 pounds for something by the town and in 1675 John Foss, Surveyor presented his account for work done on the highway, working with him were John and James Berry. He is said to have received a deed of land in Rye in 1668. New England Family History, A Magazine Devoted to the Families of Maine and Massachusetts, Henry Cole Quinby, Vol 3, page 432.
In his books on the Foss Family, Guy Rix, a blacksmith in Concord, New Hampshire, pieced together the genealogy through correspondence. This was done in the early 1900's. Apparently a Foss family in then Danish Virgin Islands wrote to him and told him of their Danish ancestry. For whatever reason Guy assigned their ancestors to all Foss's in America, which is simply not the case.
John of Rye and his English background
In a 1990 article in the New England Historical and Genealogical Register entitled "Two John Jacksons From Dartmouth" the author surmises that John Fosse, son of Steven Fosse and Mary Jackson, and great nephew of John Jackson immigrant to New Hampshire, was the John Foss of Rye. The Jackson Foss families lived in Paignton, Devon, England, which is a coastal town, and adds credence to the story of John being a caulker on a ship. Still, the article does not offer any concrete evidence that John Foss of Devon was in fact John Foss of Rye, but it sounds promising. John Plumer, "Two John Jacksons from Dartmouth", The New England Historic and Genealogic Register, Vol. 144
John and his wife Mary testified in 1706 about the last wishes of Mary's sister Rachel Marden. John deeded his property in Sept. 1710 to John, Joshua and Zachariah. If anyone has a copy of this deed I would love to see it! He died sometime afterwards.
Two sons named William
To keep things complicated both men had sons, born around the same time, named William. William, son of John Fost, is known to have been born on March 11, 1673. He married first in 1692 to Margery Lord and second Sarah, widow of Nathaniel Heard of Dover. Around 1727 he married Mary Horne. William Foss, son of John Foss of Rye, married Sarah Buswell in 1700 in Hampton Falls.
The Hampton Lane Library which is a great genealogy resource for New Hampshire Ancestors lists John Foss as the son of Steven and Mary Jackson Foss.