Sry german text only. Google translator may help.
Earlier there were pictures from the Mangeot Steinway in Berlin, Salon Christofori. They took out the pics. Text is not quite right as the moving of Mangeot to PAris took place later - at the times of the Steinway Mangeot cooperation they were a piano manufacture in Nancy, eastern France.
Theo Steinway will have had the contacts because his network of piano makers in Europe was excellent. The decision for the Mangeot bros. maybe was positive because they were no big competitors like Erard, Pleyel, Gaveau but a relatively small manufacture of high quality approach.
The Mangeot cooperation had started in 1866/67 in the sequence of one of the european fairs. Edouard Mangeot went to New York City to learn in the Steinway premises (in the 1860 inaugurated big plant 52/53 street) how to fabricate american pianos.
A real Mangeot Steinway has both names in the flap. It has a Steinway harp for which one should know that the harp in these days did NOT YET come from own casting manufacture in Ditmars, because Theo Steinway had started his own casting plant in 1872/73. At a time when I assume that the preparations for the London 1875 workshop were in their way, and the Mangeot cooperation contract may have yet been cancelled by William Steinway.
Then he sued the Mangeot bros. for counterfeiting.
So it was nasty business doing, first a good cooperation, then some "other thoughts", then a IMHO nasty behaviour to kick out the (ex) partners while leaving them (maybe) with a lot of material ordered and delivered - but not yet sold ...
OK it's business. I don't like it. I adore William Steinway for his business abilities but I am a man of honour, would never be able to act in this manner. I would have ended the contract but with the provision that the rest of the material is OK for being built and sold. When I had delivered 200 building sets, I cannot leave my partner with 135 sets unsold. Or there had to do some good cooperation in reselling the stuff, takeover of transportation costs et cetera. No single word in the Steinway diaries but only these nasty wording of "..had to go to court to stop the manufacture of counterfeited pianos..." something like this.
So we were told only the nasty end of story in 1872/73 - not the friendly beginning in 1866/67 when Theo Steinway made friend with the Mangeot Freres.
Known to me are four Mangeot Steinways as I eagerly watched the relevant websites for about ten years. Some tell that there were no bigger amounts of "Building sets" but others say that there might have been ca. 200 parlor grand building sets consisting of a harp, a soundboard and a mechanism. I don't know. The Mangeot bros. to build the cases, to install the U.S. material, to regulate, to sell the pianos in France and Great Britain. That was the initial deal.
The cooperation had started when the first good orders for Steinway grands had come from european customers also, then Theodore might have recognized that it had been a mistake to sell his shares of the Brunswick manufacture to Mr Grotrian jr, Messrs Helferich and Schulz.
That they might need again a European manufacture ... to overcome high import taxes.
I played with a 1864 parlor grand which is in the Seesen home museum, the grand had been ordered by a wealthy Hamburg family and then worked 100 yrs for the Seesen male chorus until ca. 2004.
Same design of "Henry & Henry", the second work for overstrung grands as the first design in 1858 was for concert size, but directly a derivate was done for private purposes in the 7ft size. design was finished ca. 1861.
OT - There is another grand of 1860 I regret not to have bought some years ago, also 7ft size but straight strung... It was offered in Hollywood ca. 2011 and I did not follow up this matter because I had no idea how to overcome the problems of crossing the U.S. custom authorities with ivory keys. It was #3023 I once was interested to buy. Should have cost 20.000 USD. I had the money...
A white elephant of piano history - A STRAIGHT STRUNG STEINWAY GRAND ...)
That would have been a gorgeous triple of grands ...
1- Steinway & Sons No. 3023 from 1860 in fancy style with "lion feet" - straight strung
2- Mangeot Steinway 1871 in white Queen Anne fancy style with golden lines, bordures ...
3- Steinway Centennial D 1877 ...
... don't disturb....
... author dreaming ...