I'm collecting material about UG but it will take a lot of time to organize on a series of posts.
One correction: It was Universal that cut the relations with Martel around 1955 by starting their own movement manufacture.
The challenges faced by Martel, after UG left, that made Zenith, in 1960, to acquire Martel.
Since watch history is a fascinating matter, this chain of events give as result the El Primero that, according to some sources, was a creation of the Zenith El Primero by Raoul Pellaton.
Cheers,
Nilo
This message has been edited by nilomis on 2013-03-01 01:46:58