I am a descendant of Samuel and Mary Eames through their first born Samuel, a brother of your ancester Jonathan.Your posting brought up some good points, namely the listing of Mary Death in her father Francis Peabody's will of 1695/96 which is after her supposed marriage to Samuel Eames.I'd like to share some of my thoughts and would be interested in your opinion. First, I concur that Mary is given as Mary Death in her father's will (ref. Peabody Genealogy) so it is unlikely that this is the Mary who married Samuel Eames on 6 Jan 1689.I figured a good place to start was to look into Mary Peabody's husband John Death.I came across the web site www.cc.utah.edu/~mm10a50/pearce/a10.htm which provided alot a material on John together with sources for the information.Here is some of the facts (1)John and Mary Death were married by May 1670 when their son Thomas was born in Topsfield and they were fined in March 1670 for "fornication before marriage". (2)There is a recorded deed 1 Apr 1702 involving John Death with one of the witnesses John Death, Jr.so John Death, Sr. is still alive when Samuel Eames and Mary Death were married. (3)On 30 Mar 1722, John Death deeds his estate and names his wife Mary, son Samuel, son John Death, Jr, daughters Mary Eames, Hephzibah How, Lydia Lamb, Ruth How.Thus, John Death is still alive then as an elderly man. (4) John Death names his daughters in that order.I think there are birth records for Hepzibah, Lydia, and Ruth since the web site gives birth dates and the girls were born in this order.Thus, one could infer that a daughter Mary was born earlier and married an Eames. (5)I can find no hard evidence of the birth date for Mary Peabody other than the vague, about 1656, which may have originated with the Peabody Genealogy.In her father Francis Peabody's will she (Mary Death) is listed as after daughters Lydia Perley but before Sarah How who married in 1678 and Hepsibah who married in 1678.Thus, using the normal practice that the daughters would be listed in birth order in the will I think that Mary was born earlier that 1656 and more around 1649 noting that the Peabody Genealogy gives "about 1650" for Sarah and "about 1652" for Hepsibah.An earlier birth year of 1649 rather than 1656 makes it easier to see her as marrying John Death in 1670 and more likely that it is not her that married Samuel Eames but rather the daughter of John Death and Mary Peabody.
Thus, I think the more likely lineage is Francis Peabody m. Mary Foster their daughter Mary Peabody (b. about 1649) m. John Death about 1670.John Death died later than 1722. Their daughter Mary Death (b. about 1670) m. Samuel Eames in 1689. Samuel Eames and Jonathan Eames were the sons of Samuel Eames and Mary (Death) Eames.
If someone finds any additional source information that supports or disproves this, I'd appreciate hearing from you.My guess is that all the information on the internet, etc. is based on the Peabody Genealogy of 1909 which has Mary Peabody m. (1) John Death, m. (2) Samuel Eames.But I think the sources do not support that claim.