Katherine Fiennes was born circa 1490 to Thomas Fiennes, 8th Baron Dacre (1472-1534) and Anne Bourchier (1470-1530) . She married Richard Loudenoys (c1490-) .
Children
| Name | Birth | Death | Joined with |
| Mary Loudenoys (c1516-) | 1516 | Thomas Harlakenden (c1505-c1564) | |
Siblings
| Name | Birth | Death | Joined with |
| Thomas Fiennes (-1528) | |||
| Katherine Fiennes (c1490-) | 1490 | Richard Loudenoys (c1490-) | |
| Mary Fiennes (1495-1531) | |||
| John Fiennes (1497-) | |||