Question: What year was Sidwell Friends School founded where Roderick H. Cox taught for nearly 40 years?

Context articles: Josh Hart (basketball)
Friends School of Wilmington
Tandem Friends School
J.C. Luning
Newtown Friends School
Media-Providence Friends School
Alexandria Friends School
Roderick H. Cox
Sidwell Friends School
Virginia Beach Friends School

Josh Hart (born March 6, 1995) is an American basketball player for the Los Angeles Lakers of the National Basketball Association (NBA).
 He played college basketball for Villanova.
 As a senior at Sidwell Friends School, Hart posted averages 24.3 points, 13.4 rebounds and 2.8 steals per game and was a highly recruited prospect.
 In his sophomore season at Villanova, Hart was named the Big East Tournament most outstanding player.
 As a junior, he was named to the All-Big East first team and helped Villanova win the national championship in 2016.
Friends School of Wilmington is an 18 months - 8th grade private/independent Quaker school located in Wilmington, North Carolina.
 The school was founded in 1995 by the Wilmington (NC) Friends Meeting and has grown from a middle school for 30 students to a school for 190 students.
 Friends School is located on two campuses located 2.9 miles apart with five buildings and eight acres of playgrounds, fields, gardens, woods, and a pond.
Tandem Friends School is a coeducational secondary school founded in 1970 in Albemarle County, Virginia, just outside Charlottesville, by educators John Howard and Duncan Alling.
 In 1995, it joined the Friends Council on Education, adopting the educational beliefs and practices of the Quakers.
 The current head of school is Whitney Thompson.
 The Upper School, grades 9-12, has approximately 100 students, while the Middle School, grades 5-8, has approximately 120 students.
 The head of the Upper School is Peter Gaines, and the head of the Middle School is Tom O'Connor.
 Tandem is located on 279 Tandem Lane.
 The mascot is a Quaker, though the original mascot was a badger.
 When the mascot was changed in 2015, there was a good deal of resistance from students concerning the fact that though the school is technically Quaker, very few students are Quaker.
 Students felt misrepresented, the more so since the badger was a mascot the students had chosen themselves, whereas the Quaker was imposed upon them.
 The logo is the historic main building (originally a plantation house and later a Civil War hospital), which is thought by some to be haunted.
John Christian Luning (December 21, 1863 – September 28, 1928) was a mayor of the town of Leesburg, Florida, during the 1890s and Lake County Commissioner.
 He would go on to serve the shortest term as Florida's Commissioner of Agriculture for 14 days before going on to serve as State Treasurer of Florida.
 He was part of a group of Florida leaders known as the "Three Musketeers" – along with James B. Whitfield (a state treasurer and state attorney general before serving nearly 40 years on the Florida Supreme Court) and William V. Knott (who held various cabinet positions for nearly 40 continuous years before becoming a political appointee) – and had a bright political future before his sudden death in September 1928.
Newtown Friends School is a coeducational prekindergarten through eighth grade Quaker independent school founded in 1948 and located in Bucks County, Pennsylvania.
 Though its name and address indicate it is in Newtown Township, it is physically located in Middletown Township.
 Newtown Friends' campus adjoins with that of George School.
Media-Providence Friends School is a Quaker school founded as Media Friends School in Media, Pennsylvania in 1876.
Alexandria Friends School (AFS) was a private, non-profit Friends (Quaker) middle and high school (grades 6-12) located at 3830 Seminary Road in Alexandria, Virginia, United States.
 It was founded in 2006 by faculty and staff from Thornton Friends School's Alexandria campus, which closed at the end of the 2005-2006 school year.
 The school closed in 2012, despite promises to reopen the following year.
Roderick Howard Cox (March 5, 1911 – August 25, 2000) was an American track and field athlete, football player, teacher, and environmentalist.
 He was the NCAA champion in the hammer throw in 1933 and also played for the Michigan Wolverines football team from 1930 to 1932.
 Cox later served in the United States Navy and attained the rank of commander in the Naval Reserve.
 He was a teacher at the Sidwell Friends School for nearly 40 years.
Sidwell Friends School is a highly selective Quaker school located in Bethesda, Maryland and Washington, D.C., offering pre-kindergarten through secondary school classes.
 Founded in 1883 by Thomas Sidwell, its motto is ""Eluceat omnibus lux" " (English: Let the light shine out from all ), alluding to the Quaker concept of inner light.
 All Sidwell Friends students attend Quaker meeting for worship weekly, and middle school students begin every day with five minutes of silence.
Virginia Beach Friends School (VBFS) is an independent life-skills and college preparatory day school founded in 1955 under the care of the Virginia Beach Friends Meeting.
 Virginia Beach Friends School has more than 200 students enrolled in four divisions – Early School (Cottage, Treehouse, Pre-K and Kindergarten), Lower School (Grades 1-5), Middle School (Grades 6-8), and Upper School (Grades 9-12).