FamilySearch.org family Josiah Dean and Abigail Richards. It lists their children, including ancestor child Richard, and the parents and siblings of Josiah.

Her dates of birth and death are inconsistent across sources, OR, there was more than one Abigail (Richards) Dean who were contemporaries.

Historical
1743: United States - Thomas Jefferson is born in Virginia
1744-1748: France, India - The First Carnatic War fought between the British, the French, the Marathas, and Mysore in India
1744: France - French attempt to restart the Jacobite rebellion fails
1744: Saudi Arabia - The First Saudi State is founded by Mohammed Ibn Saud
1745: England, Scotland - Second Jacobite Rebellion began by Charles Edward Stuart in Scotland
1745: United States - John Jay born
1747: Afghanistan - Ahmed Shah Durrani founded the Durrani Empire in modern day Afghanistan
1748-1754: England, France, India - The Second Carnatic War fought between the British, the French, the Marathas, and Mysore in India
1748: Austria - Treaty of Aix-La-Chapelle ends the War of the Austrian Succession and First Carnatic War
1748: United States - Benjamin Franklin retires from the printing business to pursue scientific matters
1750: Europe - Peak of the Little Ice Age [first suggested in 1939, this has since been disputed after more detailed research] that lasts another one hundred years
1751: United States - Jamaes Madison born
1752: United States - Benjamin Franklin discovers electricity with his famous kite flying experiment which was done in secrecy at the time. Later that same year he invents the lightning rod, one of the most perfect inventions because it continues to do its job without maintenance. It is still being used today by every tall building in the world.
1753: United States, France, England - Major George Washington, age 21, delivers a message to the French from the English King asking the French to leave North American, the French politely refuse
1754-1763,: United States, France, England - The French and Indian War, Fought in the U.S. and Canada mostly between the French and French allies and the English and English allies, the North American chapter of the Seven Years War
1754: India - Treaty of Pondicherry ends Second Carnatic War (of three) and recognizes Muhammed Ali Khan Wallajah as Nawab of the Carnatic
1755-1763: Canada - The Great Upheaval, forced population transfer of the French Acadian population from Nova Scotia and New Brunswick
1755: Portugal - The Lisbon earthquake
1756-1763: France, India - The Third Carnatic War fought between the British, the French, the Marathas, and Mysore in India
1756-1763: globe - Seven Years War fought among European powers in various theaters around the world
1757: India - Battle of Plassey signaled the beginning of formal British rule in India after years of commercial activity under the auspices of the East India Company
1758: England - British colonel James Wolfe Issues the Wolfe Manifesto
1758: United States - James Monroe born
1759: France, England - French commander Louis-Joseph de Montcalm and British commander James Wolfe die during the Battle of the Plains of Abraham
1760: England - George III became King of Britain
1760: Iran - Zand dynasty founded in Iran
1761: France, India - Battle of Panipat, France defeats Maratha Empire
1762-1796: Russia - Reign of Catherine the Great of Russia
1763: India - Treaty of Paris ends Seven Years War and Third Carnatic War
1763: Omdoa - Kingdom of Mysore conquers the Kingdom of Keladi
1765: United States, England - Stamp Act Introduced into the American colonies by the UK Parliament
1766-1799: India - Anglo-Mysore Wars
1767: Burma - Burmese conquered the Ayutthaya kingdom
1768-1774: Russia, Turkey - Russo-Turkish War (sixth of ten), Russian victory
1768: Nepal - Gurkhas conquered Nepal
1769-1770: New Zealand, Australia - James Cook explores and maps New Zealand and Australia
1769-1773: India - The Bengal famine of 1770 killed one third of the Bengal population
1769: United States - James Watt invents the steam engine, this begins the Industrial Revolution
1769: United States - Spanish missionaries established the first of twenty one missions in California
1770-1771: Czech Republic - Famine in Czech lands killed hundreds of thousands
1770: Australia, England - James Cook claims the East Coast of Australia (New South Wales) for Great Britain
1770: United States - Boston Massacre occurs when British troops fire into a crowd of snowball throwers, killing five. John Adams later defends in court the British troops involved, this actually boosts John Adams' reputation because it demonstrates to the British that the Americans are fair
1771: England - Richard Arkwright and his partners build the first water-powered mill at Cromford
1771: Russia - The Plague Riot in Moscow
1772-1779: England, India - Maratha Empire fights Britain and the forces of Raghunathrao during the First Anglo-Maratha War
1772-1795: Poland - The Partitions of Poland ended the Polish-Lithuanian Commonwealth and erased Poland from the map for 123 years
1772: Denmark - Reformer Johann Friedrich Struensee executed in Denmark
1772: Poland - Partitions of Poland marks the end of the Polish-Lithuanian Commonwealth
1772: Sweden - Gustav III of Sweden stages a coup d etat, becoming almost an absolute monarch
1773-1775: Russia - Pugachev Rebellion was the largest peasant revolt in the history of Russia
1773: India, China - East India Company starts operations in Bengal to smuggle Opium into China
1775-1783: United States, England - American Revolutionary War
1775: United States - Daniel Boone begins to clear the Wilderness Road to Kentucky
1775: globe - John Harrison H4 and Larcum Kendall K1 Marine chronometers are used to measure longitude by James Cook on his Second voyage (1772-1775)
1776: Germany - Order of Illuminati founded by German philosopher Adam Weishaupt
1776: United States - United States Declaration of Independence is written by Thomas Jefferson and others then is adopted by the Second Continental Congress meeting in Philadelphia
1778: United States - James Cook becomes first European on the Hawaiian Islands
1778: Vietnam - Tây So-n Dynasty established in Vietnam
1779-1879: England, South Africa - Xhosa Wars between British and Boer settlers and the Xhosas in South African Republic
1780: Peru - Outbreak of Indigenous rebellion led by Túpac Amaru II in Peru
1781-1785: Austria - Serfdom abolished in the Austrian monarchy (first step, second step in 1848)
1781: United States, Spain - Spanish settlers founded Los Angeles