‘Historical sketch’ outlines some of the notable discoveries in the field of probability research. Fermat and Pascal both showed ways of determining the winner of a series based on partial data. Jacob Bernoulli developed the Law of Large Numbers, later advanced by Borel. De Moivre discovered that deviations were linked to the square root of sample size. Bayes devised the notion of inverse probability. Laplace outlined the Central Limit Theorem. Gauss and Poisson both charted distributions which now bear their name. Markov discovered the property of forgetting in randomly varying sequences. In the 1980s, Kolmogorov placed all existing theorems into a logical framework.