At the funeral service for Nancy Reagan, actress and spouse of former president Ronald Reagan, former Canadian prime minister Brian Mulroney read a letter Ronald Reagan wrote to his wife on their first Christmas together in the White House.

He wrote about how lucky he was to have many great women in his life, including a woman who cares for the sick and elderly, a fun woman to visit the ranch with and a sentimental woman prone to laughter and tears.

"Fortunately," he wrote, "all these women in my life are you. Fortunately for me, that is, because there could be no life for me without you."

The letter said she filled his entire life with "warmth and love."

"Theirs was a love for the ages," Mulroney said. "They had style and they had grace and they had class."

Mourners from the top ranks of Washington and Hollywood paid tribute to Nancy Reagan on Friday, recalling at her funeral how she and her husband made up "two halves of a circle," with a legendary love that seemed to inspire everyone they met.

Inseparable in life, the pair are to be reunited in death in side-by-side graves at the Reagan presidential library.

During a service filled with poignant and often humorous memories, each speaker came back to the couple's love story.

"When they were together, he hid love notes around the house for her to find," said Reagan's former chief of staff, James Baker. "She reciprocated by secreting little notes in jellybeans in his suitcase.

Obit Nancy Reagan

This December 1986 photo shows Nancy Reagan holding pet Rex, a King Charles spaniel, as she walks outside the White House with her husband Ronald, who served as U.S. president from 1981-1989 (Dennis Cook/Associated Press)

"Ronald and Nancy Reagan were defined by their love for each other," Baker added. "They were as close to being one person as is possible for any two people to be."

Although many speakers invoked the former president's name, they were also quick to add that Nancy Reagan was more than just a supportive wife. She was a force of nature herself.

"There would be no Ronald Reagan presidential library without a president Ronald Reagan, and there likely wouldn't have been a president Ronald Reagan without a Nancy Reagan," said the couple's son, Ron Jr.

It was her belief in what her husband could accomplish that gave his father the "chutzpah" to seek political office, he added.

'They complemented one another'

"It would be a mistake, by the way, to consider her as somehow subordinate to him just because he was the one usually taking the centre stage," Ron Reagan said. "They were co-equals. They complemented one another."

While her husband was affable, Nancy Reagan could be loving, friendly and quick to laugh. But, if anyone did anything she thought was harmful to her husband, she was fiercely protective and sometimes quick to anger.

When former NBC anchor Tom Brokaw once questioned the hard-luck story of the president's early life, Brokaw recalled how she was so angry that her husband's staff advised him to stay away from the White House until she calmed down.

Ronald Reagan didn't mind the criticism, Brokaw said, but his wife did.

"Occasionally I've thought that even God might not have the guts to argue with Nancy Reagan," the couple's daughter, Patti Davis, quipped.

Nancy Reagan

Honour guards stand near the casket of Nancy Reagan at the Reagan presidential library, in Simi Valley, Calif., on Thursday. (Jae C. Hong/Associated Press)

A waterproof tent was put up behind the library to shield its 1,000 invited guests from a rainy forecast. Although it sprinkled lightly during the 90-minute ceremony, there was a downpour near the conclusion, forcing guests to open umbrellas as they left.

Among those in the front row were Michelle Obama, who was seated next to former president George W. Bush. Hillary Clinton sat between Bush's wife, Laura, and former presidential spouse Rosalynn Carter.

The sprawling, Spanish mission-style library is located between the Reagans' post-White House home in the upscale Bel Air section of Los Angeles and Rancho del Cielo, the "ranch in the sky" where the Reagans spent their leisure time, sometimes on horseback, in the rugged mountains near Santa Barbara.

The guest list for the funeral tells a story about their lives, which stretched from Hollywood's Golden Age to the California statehouse during Ronald Reagan's time as governor, to Washington. Four of the five living presidential spouses, and relatives of every president dating to John Kennedy were in attendance.

Mourners included former Reagan administration official Ed Meese, former House Speaker Newt Gingrich, Mike Love of the Beach Boys and singer Johnny Mathis.

As the group gathered briefly outside the library to chat, Mathis reminisced about how he and Nancy Reagan would sing together during his visits to the Reagan family home. Their favourite song was Our Love is Here to Stay.

Democrats and Republicans united

The memorial service brought together Democrats and Republicans at a time of deep division in Washington and on the 2016 campaign trail.

On Wednesday and Thursday at the library, more than 5,500 mourners filed slowly past the Nancy Reagan's closed casket, blanketed with white roses and peonies, her favourite flower.

Tears often fell. The crowd, many in graying years, spoke to a time when it was "morning again in America" and the nation followed the Reagan doctrine to weaken Soviet influence during the Cold War.

Ronald Reagan left the presidency after eight years, on January 20, 1989.

Nancy Reagan, who died Sunday at 94, planned the smallest details of her funeral. 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.

The library site, where the 40th president was buried in 2004, provides sweeping views of horse country dotted with oaks and, on a clear day, a vista to the Pacific.

The Reagans "just fell in love" with the spot, Boston developer and Republican fundraiser Gerald Blakeley recalled in a 2004 interview. He was part of a partnership that donated the land where the library now sits.

With files from CBC News