Historically, the merger doctrine (a.k.a. "doctrine of merger") was the notion that marriage caused a woman's legal identity to merge with that of her husband.

Thus, a woman could not sue

Sue

Sue or SUE may refer to:* Door County Cherryland Airport in Sturgeon Bay, Wisconsin, USA* The action of filing a lawsuit.* Subsurface Utility Engineering* .sue, alternative name for ARC -Places:...

 or testify against her husband any more than he could sue or testify against himself. Since her identity had merged with his, the two were now considered one legal entity.

See also

• Merger doctrine (civil procedure)
  Merger doctrine (civil procedure)
  The merger doctrine in civil procedure stands for the proposition that when litigants agree to a settlement, and then seek to have their settlement incorporated into a court order, the court order actually extinguishes the settlement and replaces it with the authority of the court to supervise the...
  
  
• Merger doctrine (property law)
  Merger doctrine (property law)
  In the law of real property, the merger doctrine stands for the proposition that the contract for the conveyance of property merges into the deed of conveyance; therefore, any guarantees made in the contract that are not reflected in the deed are extinguished when the deed is conveyed to the buyer...
  
  
• Merger doctrine (trust law)
  Merger doctrine (trust law)
  In the law of trusts the term "doctrine of merger" refers to the fusing of legal and equitable title in the event the same person becomes both the sole trustee and the sole beneficiary of a trust...
  
  
• Coverture
  Coverture
  Coverture was a legal doctrine whereby, upon marriage, a woman's legal rights were subsumed by those of her husband. Coverture was enshrined in the common law of England and the United States throughout most of the 19th century...