19 июня 1669 года родился Леонтий Телятин

A self-taught son of a peasant learned how to read and count, went through a difficult journey to the Slavic-Greek-Latin Academy, and became famous for what the academy did not teach at the time – mathematics. In mysterious ways, he met Tsar Peter and left a stunning impression. “Because of the affection of the disciples, you, Leonty, like a magnet surrounded by sawdust, should be Magnitsky from now on!" Peter commanded. He appointed Magnitsky as a teacher at the school of navigational sciences and instructed him to write a textbook on mathematics. The most famous Magnitsky's Arithmetic is a book that, along with a grammar book, was later named the gates of his learning by Mikhail Lomonosov himself. It was the first Russian scientific and technical book, if you call a pikestaff a pikestaff.