While not as “mainstream” as some other piano makers, Mason and Hamlin is considered by many to be one of the finest manufacturers of all time.  Originally an organ company, this ad (1880) is from right around the time when Mason and Hamlin first began making pianos, as well.

FUN FACT:  Mason & Hamlin is known for its innovative Tension Resonator, which “adds strength and rigidity to the rim by locking the rim into its permanent shape and which in turn preserves the ‘crown’ of the soundboard.”  (Source:  Wikipedia)