(ABT 1517-ABT 1573)
+---Richard Trethewy (BEF 1550-)
+---Anthony Trethewy (-JUN 1625)
| | +---William Hawkins
| +---Joan Hawkins 
(ABT 1530-)
+---Lewis Trethewy (AFT 1619-ABT 1693)
| +---Elizabeth ? (-ABT 1644)
+---John Trethewy
| +---Elizabeth Arundell
+---Robert Trethewy (ABT 1698-AUG 1771)
| +---Elizabeth ? (-JAN 1708)
+---Henry Trethewy (ABT 1734-APR 1784)
| +---Grace Rogers (-SEP 1772)
+---Henry Trethewy (ABT 1779-09 MAR 1869)
| +---Charity Richards
+---Henry Chambers Trethewy (ABT 1807-07 JUN 1899)
| +---Ann Chambers (ABT 1776-04 JUN 1809)
+---Henry John Trethewy (ABT 1838-07 NOV 1890)
| +---Mary Ann Thompson (ABT 1805-03 MAY 1875)
+---Arthur Thomas Trethewy (29 DEC 1875-1943)
| | +---Thomas Russell
| +---Catherine (Kate) Russell (ABT 1842-11 JUL 1894)
Russell Andrew Trethewy
+---Alice Harrington