This is what I could find on tomatoville.
The variety Green Copia is a different matter as indicated in the link above.
Whether it's Green Copia or Harvard Square I don't know if anyone can be sure. What it's not is a GWRipe variety.
I looked in the 2010 SSE YEarbook trying to figure out the dates of introduction and who sent what to whom and when, and Andrey did say a US source for Copia and said he named it Green Copia b'c it didn't look like Copia and said he grew them in 2006 and 2007.
Tania says 5-10 oz , seeds from France and Andrey says 200 to 500 grams, so some fruits can be over a pound.
Additional info at Tania's site says Andrey got the seeds in 2004/2005 for what he called Green Copia from John H of Moscow Idaho who sent him the variety Copia.
For Harvard Square Martin apparently first listed this one in 2006 and says seeds from an individual in Sparta, WI, which must be not that far from him since Martin also lives in WI. Martin says tri-color beefsteak up to a pound and light green plus red stripes.
Neil L says bi-color fruit, says 4-8 oz and seeds from Martin in 2006. Al Anderson says multi-color green/yellow/orange and red and says 6-8 oz.
Interesting that no one says anyhing at all about taste.
For Green Copia both Tania and Andrey say sweet taste.
In the 2006 YEarbook there is no listing for either Harvard Square or Green Copia.
In the 2007 Yearbook there is a listing for Harvard Square by Martin and no Green Copia listing.
Both Neil and Al say they got the seeds from Martin in 2006 and even tho Martin didn't list it until 2007 I don't find that unusual b/c I've sent seeds from a season in the Fall when the Yearbook listing wouldn't come out until the next late Jan/Feb.
OK, so put the dots together.
I'm leaning towards Martin getting the seeds from someone in WI, but Martin doesn't say when he got the seeds, but I can't see Martin sitting on seeds as early as 2004/2005 when Andrey said he got the seeds from John H in Idaho that were Copia seeds, without listing them as he did in 2007 and could have distributed seeds for them in the Fall of 2006.
So is John H in Idaho the original person who found and named it Harvard Square, not likely since he sent Copia seeds to Andrey,or did Martin name it Harvard Square but his source for what he named harvard Square was not John H. of Idaho.
The earliest reference to Copia morphing into Green Copia is Andrey receiving seeds from John H in 2004/2005, so whout further data it seems that there was a cross or mutation in JOhn H's tomato patch of Copia and those seeds sent to Andrey.
Tania mentions that Green Copia is not genetically stable.
About the French connection. Andrey trades seeds with lots of folks all over the place and it seems reasonable to suggest that he traded seeds of what he called Green Copia with the French source(s) Tania lists.
It is a big yummy sweet tomato with just a touch of tartness on the finish, sliced thick on a good bagel with cream cheese, you will thank me.
The fruits get to 10-15oz some getting bigger?