(ABT 1517-ABT 1573)
+---Thomas Trethewy (-ABT 1616)
+---Bartholomew Trethewy
+---Bartholomew Trethewy (-1666)
+---Bartholomew Trethewy
+---Thomas Trethewy (ABT 1675-MAY 1743)
| +---Jane Bruart 
+---Thomas Trethewy (ABT 1710-FEB 1795)
| | +---Phillip Mellow (ABT 1660-JAN 1711)
| +---Joan Mellow (ABT 1680-)
| +---Jane ?
+---William Trethewy (ABT 1740-OCT 1814)
| | +---Richard Jolliffe
| | +---Robert Jolliffe
| | +---Robert Jolliffe (ABT 1546-1602)
| | +---Henry Jolliffe (ABT 1586-)
| | | +---Thomason ?
| | +---Francis Jolliffe (ABT 1622-)
| | | +---Blanch Pearce
| | +---James Jolley (ABT 1682-APR 1754)
| | | +---Rose May
| +---Elizabeth Jolley (ABT 1713-)
| | +---Richard Osborne (-JUN 1667)
| | | +---Eme Varcoe
| | +---Richard Osborne
| | | +---Joan ?
| | +---Richard Osborne (-NOV 1707)
| | | | +---Arthur Michell (-ABT 1657)
| | | +---Constance Michell (ABT 1635-APR 1717)
| | | | +---Thomas Corne (-1647)
| | | +---Blanche Corne
| +---Blanche Osborne
| +---Bettres ?
+---William Trethewy (ABT 1779-)
| | +---Edward Brokenshaw (-ABT 1644)
| | +---Francis Brokenshire (ABT 1615-)
| | | +---Agnes ?
| | +---Francis Brokenshire
| | | +---Dorothy ? (-OCT 1658)
| | +---Benjamin Brokenshire
| | | | +---John Mock (-OCT 1609)
| | | | +---Lancelot Mock (-FEB 1631)
| | | | | +---Joan ? (-OCT 1609)
| | | | +---Richard Mock (ABT 1614-1694)
| | | | | +---Joan Webber (-1623)
| | | +---Mary Mock
| | +---Joseph Brokenshire (-DEC 1777)
| | | +---Margery ?
| +---Jane Brokenshire (ABT 1747-)
| | +---John Kent (-MAR 1709)
| | | | +---Robert Kent (-JAN 1593)
| | | | +---John Kent (ABT 1562-JAN 1638)
| | | | | +---Elizabeth Davie (-JUN 1612)
| | | +---Emblyn Kent (ABT 1598-APR 1670)
| | | +---Jane ?
| | +---Robert Kent (-MAY 1692)
| | | | +---Bawden Woodman (-ABT 1615)
| | | | +---Richard Woodman
| | | | | +---Eme Varcoe
| | | +---Elizabeth Woodman (-JUN 1696)
| | | +---Dorothy ? (-ABT 1684)
| | +---John Kent (-SEP 1761)
| | | +---Grace ? (-MAY 1724)
| +---Jane Kent (ABT 1717-)
| +---Jane ?
+---James Trethewy (ABT 1821-)
| +---Grace ? (ABT 1784-OCT 1836)
+---William Trethewy (ABT 1845-)
| | +---John Bullen
| +---Jenefer Bullen (ABT 1822-)
| | +---Solomon Whitford (ABT 1754-)
| | | +---Jane ?
| +---Susanna Whitford (ABT 1785-)
| +---Susanna Bedick
+---James Bassett Trethewy (ABT 1876-05 NOV 1918)
| +---Susan Bassett (ABT 1850-)
Croydon James Trethewy
+---Emily Lousia Ann ? (-19 MAR 1934)