In the context of ageing and other degenerative processes, the truly modern era may be seen as beginning around the early to middle of the nineteenth century. Thus in 1817 one James Parkinson, born in 1755, a Londoner who had in 1784 been approved by the City of London Corporation as a surgeon, and the equivalent of a modern GP, wrote his ground-breaking ‘Essay on the shaking Palsy’. Parkinson’s essay is so insightful, so accurate and comprehensive that it bears comparison with a modern account, clinical or academic, of his disease, though it must be acknowledged that nearly 2,000 years ago Galen had described the shaking palsy, and even earlier similar mention is made in the Ayurvedic texts of ancient India. Age of onset is certainly an important factor in how Parkinson’s continues to develop, and also in Friedreich’s ataxia, though whether or not this is simply a consequence of heterogeneity in a disorder is a moot point.