William James Sidis (1898 – 1944) During his life, his ratio IQ was estimated to be between 250 and 300, making it one of the highest ever recorded but the testing was different from standard IQ tests. He entered Harvard at age 11 and, as an adult, was claimed to be conversant in over forty languages and dialects. Sidis created a constructed language called Vendergood in his second book, which he wrote at the age of eight.
William James Sidis, shown here in his 1914 graduation photo, received his degree from Harvard University at age 16. He qualified for admission when he was 9, but he was not invited to attend until age 11, when faculty thought he would be more mature, biographer Amy Wallace says.