RILM abstract: "The organ, harpsichord, clavichord, and piano have different articulative characteristics due to their actions. An apparent norm of nonlegato playing for secular music existed prior to 1600, with probable playing of notes in ligatures. Signs specific to Articulation began to appear in the 17th c. The articulatory quality of short slurs is discussed, and the persistence of nonlegato into the early 19th c. is illuminated. Changes in the piano and in styles of Articulation went hand in hand in the 19th c. In the 20th c., new signs were added by composers seeking greater specificity of articulative color."
Rosenblum, Sandra P.
"Concerning Articulation on Keyboard Instruments: Aspects from the Renaissance to the Present,"
Performance Practice Review:
1, Article 4.
Available at: http://scholarship.claremont.edu/ppr/vol10/iss1/4