This Frans De Lange, born in 1740, is the son of Arie De Lange, known as Arie of Beekman, who was the son of Frans De Lange born in Ulster Co. NY in 1681. The Frans born in 1681 was the firstborn son of immigrant Arie Franssen De Langet and Rachel Jensen Pier (Pier). The immigrant Arie Franssen De Langet subsequently had THREE grandsons named Arie; one born to the immigrant's son Frans (b.1681), one born to his son Jan Johannes (b. 1690) and one born to his son Jonas (b. 1696). Those 3 "grandson" Aries have respective birthdates of 1705, 1712/13 and 1719. They were all first cousins. To further muddy the waters, Arie who was born in 1719 then named HIS son Arie, who was born in 1756. I hope this helps someone! It took me quite a while to sort this out.
