They quickly became fashionable and this demand led other instrument makers to follow suit. Amongst Zumpe's contemporaries were such makers as Christopher Ganer, Johannes Pohlmann, Frederick Beck and Adam Beyer. The instruments started to gain complexity with the introduction of hand stops, knee levers, swell pedals, as well as more decorative casework.

Other makers such as John Broadwood, Longman and Broderip, Clementi and Sébastien Erard advanced the square piano with more sophisticated actions, dampers and the replacement of hand stops with pedals.

The size of the instruments began to grow to accommodate a greater compass of notes and their stands evolved from a simple trestle on to a 'French' stand with tapered legs through to six delicate turned legs and later four much heavier turned legs. Out of desire for greater volume the mass of the stringing increased bringing much higher tension to the pianos; metal hitch plates were introduced to alleviate the strain, followed by full metal re-inforcement. This increase in size and weight distanced the square piano from its core domestic market and during the 1850s, mass production in England declined and over the following twenty years production dwindled altogether, although production did continue in America for a further twenty years. The position in society held by the square piano is now neatly filled by the upright piano.