{"id":618215,"date":"2026-01-18T19:03:07","date_gmt":"2026-01-18T18:03:07","guid":{"rendered":"https:\/\/cronologia-universale.it\/1541-2\/"},"modified":"2026-01-18T19:03:07","modified_gmt":"2026-01-18T18:03:07","slug":"april-30-1509","status":"publish","type":"post","link":"https:\/\/cronologia-universale.it\/en\/april-30-1509\/","title":{"rendered":"April 30, 1509"},"content":{"rendered":"<p>Leonardo wrote on a sheet of the Codex Atlanticus several personal notes regarding his forthcoming book, De ludo geometrico: among the topics listed were thirteen graphic (not arithmetic) solutions to squaring the circle. Intellectual interest in squaring, which had been high for centuries, came to an abrupt halt in 1882 when Ferdinand von Lindemann, a scientist and professor at the University of K\u00f6nigsberg, demonstrated that squaring the circle is impossible, arguing that the constant \u03c0, the ratio of a circle&#8217;s circumference to its diameter, is an irrational number.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Leonardo wrote on a sheet of the Codex Atlanticus several personal notes regarding his forthcoming&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[43],"tags":[],"class_list":["post-618215","post","type-post","status-publish","format-standard","hentry","category-vg-en"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.0 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>April 30, 1509 - Cronologia Universale<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/cronologia-universale.it\/en\/april-30-1509\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"April 30, 1509 - Cronologia Universale\" \/>\n<meta property=\"og:description\" content=\"Leonardo wrote on a sheet of the Codex Atlanticus several personal notes regarding his forthcoming...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/cronologia-universale.it\/en\/april-30-1509\/\" \/>\n<meta property=\"og:site_name\" content=\"Cronologia Universale\" \/>\n<meta property=\"article:published_time\" content=\"2026-01-18T18:03:07+00:00\" \/>\n<meta name=\"author\" content=\"Rick\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Rick\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/cronologia-universale.it\/en\/april-30-1509\/\",\"url\":\"https:\/\/cronologia-universale.it\/en\/april-30-1509\/\",\"name\":\"April 30, 1509 - 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