Either on January 15, 1555 (the date in her inquisition postmortem), or January 22, 1555 (the date on her tomb), Jane Dudley, Duchess of Northumberland, died. My piece about her will can be found here. She was buried on February 1, 1555.
The duchess’s cause of death is unrecorded, although experiencing the deaths of her husband and two of her sons within the span of a year and a half, plus the loss of her wealth and status, can have hardly helped her physical well-being. Whether Jane suffered from poor health in the years before her death is unclear. A 1548 letter in which her husband asked that the surgeon of Boulogne be allowed to remain with a woman who was in danger of losing her leg refers not to Jane herself, as stated in some older sources, but to another lady. On the other hand, her husband John Dudley, then the Earl of Warwick, wrote early in Edward VI’s reign that “my wyfe hath hadd herr Fytt agayne more extremer then she hadd any tyme yet,” which could suggest that Jane had bouts of ill health, but since the earl then goes on to say that Lady Clinton had been ill and that he himself had “escap[ed] the Fytt w[hi]c[h] I dyd loke for yester daye,” perhaps Jane’s illness was simply a passing malady that had affected the whole household.
The duchess died at Chelsea, where she had been allowed to live after her husband’s execution. Although in her will she asked that her debts be paid and money given to the poor instead of “any pompe to be shewed upon my wreched carkes,” she was buried with some style. As Henry Machyn, who recorded details of numerous aristocratic funerals at the time, noted:
[The j day of February was buried the duchess of Northumberland at Chelsea where she lived, with a goodly herse of wax and pensils, and escocheons, two baners] of armes, and iiij [banners of images, and] mony mornars, and with ij haroldes of armes. Ther was a mageste and the valans, and vj dosen of torchys and ij whyt branchys, and alle the chyrche hangyd with blake and armes, and a canepe borne over her to the chyrche.
Jane’s tomb at Chelsea Old Church still exists; a brass of Jane and her five daughters (the two who survived her and the three who died young) can be seen here. An accompanying brass, presumably of Jane’s husband and sons, has disappeared. The church suffered heavy damage during the Blitz; Jane, a resilient woman, would no doubt have been pleased at the survival of her tomb.