Hannah was christened on 10 May 1761 in Bicester. Her father is listed as William HORWOOD, but no mother is given.
She was the wife of Thomas MORTIMORE. They were married on 21 October 1782 in Bicester. William HORWOOD, her brother or her father, was a witness.
Hannah had herself been a witness to the marriage of her brother William HORWOOD to Margaret MORTIMORE in December 1781. Perhaps another marriages between the same families.
Hannah Horwood and Thomas Mortimore had nine children together between 1785 and 1802: William, Ann, William, Robert, Thomas, Judith, Martha, James and James.
Hannah died in about 1802/3 and Thomas remarried and had a further child, Joseph in 1804.
Some genealogical notes:
According to IGI, both Hannah and Ann (an older sister) died on 30 Sep 1768, however this is unlikely and probably wrong. Unfortunately IGI have a habit of assuming that Ann and Hannah are the same person and have probably entered a burial date against both.
Hannah Horwood is identified as the mother of Martha Mortimer through her marriage to Thomas Mortimore. There are two marriages satisfying the following criteria: Thomas Mortimer (Exact Spelling: Off), Marriage, 1762 - 1802, County of Oxford, England, British Isles,
Spouse: Hannah. One is Ann KING in 1771 - i.e. wrong name and wrong year. The other is Hannah HORWOOD. It is not unreasonable to think therefore that Hannah HORWOOD is the Hannah that married and raised a family in Bicester, and that Martha MORTIMER is her daughter.