Patricia Larsen (plaintiff) became sick due to the alleged medical malpractice of the Mayo Medical Center (Mayo) (defendant). The two-year statute of limitations on Larsen’s claim began to run on July 24, 1996. Larsen filed suit in federal district court under its diversity jurisdiction on May 29, 1998. Federal Rule of Civil Procedure (FRCP) 4(d)(2) allows a plaintiff to request that a defendant waive personal service of the summons by mailing the complaint with an acknowledgment form, which the defendant then signs and returns. Larsen mailed the summons, complaint, and acknowledgment form to the “Medical/Legal Department, Mayo Clinic” on June 1. Mayo received the summons but would not sign and return the acknowledgment form. Larsen again attempted to mail process on June 22, but Mayo again refused to sign and return the acknowledgment. Each time, Larsen’s attorney called Mayo’s attorney, who said that Mayo would not waive service. Larsen mailed the summons and complaint to the sheriff’s department on September 4, which was received on September 8. The sheriff served Mayo the following day. Mayo moved for summary judgment on the ground that Larsen’s claim was barred by the statute of limitations. The district court granted summary judgment for Mayo, and Larsen appealed to the United States Court of Appeals for the Eighth Circuit.