SIMI VALLEY, Calif. (KABC) --Close friends, dignitaries and family remembered former first lady Nancy Reagan as her husband's chief protector during her funeral service held at the Ronald Reagan Presidential Library in Simi Valley Friday.
MORE: Videos from the Nancy Reagan funeral service
The program began with military service members bringing the casket in front of mourners and a prayer by the Rev. Stuart A. Kenworthy, vicar of the Washington National Cathedral. The Santa Susana High School Choir sang "The Battle Hymn of the Republic," and Nancy Reagan's niece Anne Peterson read from Proverbs.
Former Canadian Prime Minister Brian Mulroney read an adoring letter written by Ronald Reagan to his wife on their first Christmas in the White House in 1981. The letter said she filled his entire life with "warmth and love."
MORE: Christmas letter from President Ronald Reagan to Nancy Reagan
Former Reagan administration official James Baker recounted the first meeting of then-Nancy Davis and Ronald Reagan, and later her devastation when her husband was wounded in an assassination attempt.
"Ronald and Nancy Reagan were defined by their love for each other," Baker said. "They were as close to being one person as it is possible for any two people to be."
Veteran television journalists Diane Sawyer and Tom Brokaw also shared their recollections of Nancy Reagan.
Daughter Patti Davis described to mourners Friday how Nancy Reagan was adamant about reuniting with her husband, who died in 2004. Davis described her parents as "two halves of a circle," recalling a long-ago memory of seeing the two of them sitting on a beach at sunset in what she called an impenetrable "island for two."
Son Ron Prescott Reagan told the guests there likely would not have been a President Ronald Reagan without Nancy Reagan, saying she had an absolute belief in him, as well as provided guidance and a refuge.
Friday's service ended with recollections and prayers by Kenworthy and a bagpipe recessional as military service members carried the casket to the grave site. Her children stood by as "God Bless America" was played.
Just as she was always by his side in life, Nancy Reagan's casket will be lowered into the hillside tomb just inches beside the former president Friday night.
PHOTOS: Politicians and notable figures pay their respects at Nancy Reagan's funeral
Four of the five living first ladies and relatives of every president dating to John Kennedy attended the funeral, which also brought together Democrat and Republican, an unusual tableau at a time of deep division in Washington and the 2016 campaign trail.
Hillary Clinton took a break from the presidential campaign to attend, as did other politicians, including Newt Gingrich to Nancy Pelosi.
The service took place on the library's lawn. A tent was erected over the site of the service due to threat of rain and possible thunderstorms forecast for Friday afternoon.
The former first lady planned the smallest details of her funeral before her death. She selected the funeral's flower arrangements, the music to be played by a Marine Corps band and the list of guests invited to the private memorial.
Lines of mourners visited the library on Wednesday and Thursday to see the former first lady's flower-draped casket and pay their respects.
"Ronald Reagan was one of the best presidents we've ever had, and I admired them both as a couple for their love story and the support they showed to each other," said retired school teacher Mary Ellen Gruendyke, from Riverside.
Nancy Reagan died of congestive heart failure at her Bel-Air home Sunday morning. She was 94. Ronald Reagan died on June 5, 2004.
The Associated Press contributed to this report