Widow conservation was a practice in Protestant Europe in the early modern age, when the widow of a parish vicar (or sometimes her daughter) would marry her husband's successor to the vicarage to ensure her economic support. The practice was common in Scandinavia (Änkekonservering/Enkekonservering) and Protestant parts of Germany (Konservierung von Pfarrwitwen). It is related to other forms of widow inheritance, including the levirate marriage known in the Old Testament as yibbum.

At the introduction of the Protestant Reformation, priests were allowed to marry. However, as they did not own the vicarage and property attached to their profession, their wife and children were left without a home and means of support after their death. The future support of the widows and children of vicars thereby became a concern for the various churches. The most common solution was for the successor of a vicar to be required to marry the widow (or perhaps her daughter) of his predecessor, thereby "conserving" her.

In the United Kingdoms of Denmark and Norway, the Kirkeordinansen or Church charter of 1537, issued by Christian III of Denmark after the Reformation in Denmark–Norway and Holstein, secured for the widows of priests the right to a naadensaar (year of grace), during which they were secured an income from the parish of their late husbands and residence at the vicarage. Other than that, however, nothing was done to provide for priests' widows, and when the year was over, they were left to support themselves as well as they could, often as midwives or by some small business enterprise in the closest town. In 1566, a recommendation was issued in which priests were lectured to show mercy to the widows of their predecessors and let them stay in the vicarage, and some vicarages established a widow's house adjoining their vicarage.

This proved to be insufficient, and by the early 17th century, it had become customary for a parish to elect a vicar on condition that he marry the widow of his predecessor. There was never any formal law to require this, and if the parish protested to the authorities against a vicar who broke his promise after having been elected, their complaints were given no support by the crown. However, in practice, this was an accepted custom which vicars adjusted to, and during the 17th century it was not uncommon for a woman to have been married to four priests in succession.

In 1659, the first local pension fund for vicars' widows was established. This gradually became a more popular option, but some parishes continued to practise widow conservation until the late 18th century.

In Mark Brandenburg, widow conservation was a common practice in the 17th century. In 1698, Frederick III of Brandenburg banned widow conservation by the Juramentum simoniae, as being a form of purchase of the vicarage office.

Widow conservation was a common practice in East Prussia. The practice was the center of the legend of Ännchen von Tharau, which was inspired by the case of Anna Neander (1615–1689).

The first widow conservation in Mecklenburg is documented from 1551, and by 1580 it had become a common practice, which was recommended by the church order of 1602. By 1704, one third of all vicars' wives were the widow of the vicar's predecessor.