Music is a fundamental human construct, and harmony provides the building blocks of musical language. Using the Kunstderfuge corpus of classical music, we analyze the historical evolution of the richness of harmonic vocabulary of 76 classical composers, covering almost 6 centuries. Such corpus comprises about 9500 pieces, resulting in more than 5 million tokens of music codewords. The fulfilment of Heaps’ law for the relation between the size of the harmonic vocabulary of a composer (in codeword types) and the total length of his works (in codeword tokens), with an exponent around 0.35, allows us to define a relative measure of vocabulary richness that has a transparent interpretation. When coupled with the considered corpus, this measure allows us to quantify harmony richness across centuries, unveiling a clear increasing linear trend. In this way, we are able to rank the composers in terms of richness of vocabulary, in the same way as for other related metrics, such as entropy. We find that the latter is particularly highly correlated with our measure of richness. Our approach is not specific for music and can be applied to other systems built by tokens of different types, as for instance natural language.

音乐是人类的基本结构，和谐是音乐语言的基石。使用Kunstderfuge在古典音乐语料库中，我们分析了 76 位古典作曲家的和声词汇丰富度的历史演变，涵盖了近 6 个世纪。此类语料库包含约 9500 条，产生超过 500 万个音乐码字令牌。满足 Heaps 定律关于作曲家的和声词汇大小（以代码字类型表示）与其作品总长度（以代码字标记表示）之间的关系，指数约为 0.35，允许我们定义一个相对度量具有透明解释的词汇丰富性。当与考虑的语料库结合时，该度量使我们能够量化跨世纪的和谐丰富度，揭示了一个明显的线性增长趋势。通过这种方式，我们可以按照词汇丰富程度对作曲家进行排名，就像其他相关指标一样，比如熵。我们发现后者与我们对丰富度的衡量尤其高度相关。我们的方法不是专门针对音乐的，可以应用于由不同类型的标记构建的其他系统，例如自然语言。