Alpa from Switzerland was among the very first to produce a pentaprism SLR, though not really eye level, when they launched their Prisma Reflex in 1949, after having established the company in the late 30s. Their first cameras were waist level slrs
from early '44. (Model 1). They made high quality cameras, but never sold in big quantities and struggled economically. Towards the end of the 70s they had to give up their own production of 135 mm film cameras, but produced some cheaper cameras with Chinon
in Japan around 1980. They still earned the reputation of a high class producer of bigger format cameras until 1990, when they had to end production. In 1998, however, the brand name was reestablished by new owners, restarting the company as a hi class producer
of medium format cameras.
Alpa was one of four "Eye Level" SLR producers who started series production before the end of the 40s.
For more about that, see The Origin chapter.