Establishing that the disease was known before 1817 merely serves to confirm the talents of James Parkinson. It was moreover due to his extraordinary skill that he was able to compile disparate observations into a coherent whole, while linking them to descriptions made by his illustrious predecessors. Thus, in “An Essay on the Shaking Palsy”, Parkinson also references the writings of Claudius Galenus (129–216), Franciscus de le Boë (Sylvius; 1614–1672), William Cullen (1710–1790) and François Boissier de la Croix de Sauvages (1706–1767).

A timeline was constructed for descriptions of parkinsonism prior to James Parkinson, based on data in the literature and my own sources.

The most convincing description before 1817 must be attributed to the Hungarian Ferenc Pápai-Páriz (1649–1716), who highlighted the four essential characteristics: bradykinesia, postural imbalance, rigidity and tremor. Yet, traces of what could be descriptions of Parkinson's disease can be found much earlier in, for example, the oldest Chinese medical treatise (Huang Di Nei Jing Su Wen), and in treatises of Hindu traditional medicine on Kampavata (Parkinson's disease;±1000 BC) describing parkinsonian signs and symptoms. Symptoms such as bradykinesia were most likely not as unknown as one might think. In a book of remedies printed for the first time “on the 5th day of the month of May 1678” and intended for “esteemed and charitable Ladies”, a description of “imperfect paralysis, cramps and lethargy of the limbs” can be found that is reminiscent of hypokinesia, which is then contrasted with paralysis due to motor deficit. Last but not least, there are texts in the world literature wherein references to parkinsonian symptoms can be found, including the texts of The Iliad and Old and New Testaments of The Bible, and in the writings of Leonardo da Vinci (1452–1519) and William Shakespeare (1564–1616).

The data summarized here are merely a pale reflection of the medical literature offering abundant evidence of the existence of Parkinson's disease before Parkinson.