Nancy, who was born in 1913, is older than the Republic of Ireland itself: she was born when Ireland was still under British rule, 3 years before the Easter Rising, 9 years before the end of the War of Independence and 36 years before it was officially declared a Republic.
The County Meath woman went viral during the lockdown last year, when she made the most of not being able to attend mass in her local church, instead opting to attend virtual masses in all 32 counties in Ireland.
After watching masses in the parish of every Irish county, Nancy went further afield, and as her viral fame grew she received invitations to attend virtual mass in other countries-- including the UK and the United States.
Nancy, who was a great-great-grandmother, was living with her granddaughter Louise Coghlan since the beginning of the lockdown in March 2020, making her the oldest woman in Ireland to live in her own home.
Louise often posted the pair's adventures to the popular Facebook page Living and Laughing With Lou, which boasts almost 10,000 followers.
Usually posting photographs of the pair enjoying a cup of tea together, Nancy praying or one of Louise's countryside walks, on Friday Louise posted a devastating new update: "My best friend left for heaven this morning at 6am.
"She didn't tell me she was leaving but god came & took her to her forever home beyond the blue sky & right beside the sun, the moon & the stars."
She went on to say that she was broken-hearted but forever grateful to Nancy,"who gave me all I need to see the world in a forever kind & generous way.
"I love you granny."
Nancy's death notice on RIP.ie drew hundreds of messages of condolences, both from those that knew her and her large extended family, and those who got to know her from her virtual adventures over lockdown.
One message offered their "sincere sympathy" to the Stewarts, describing Nancy as "an inspiration to us all in difficult times."
Another praised Nancy's "fantastic legacy of love and positivity for all her family and the wider community to treasure.
"Rest assured she has gone to her heavenly reward. Gone but not forgotten. You are all in our thoughts and prayers at this sad time."
At her age, with such a large family and being much-loved in the community and afar, in normal time Nancy's funeral would have been an enormous affair-- but with the continued restrictions surrounding the Covid-19 pandemic, the numbers allowed to attend the service were limited.
Instead, Louise shared a livestream of her beloved grandmother's funeral on her Facebook page, allowing anyone who wished to attend the service to do so virtually, writing: "I know there are so many good people in the world and I know I might be slightly biased but I really think granny was beyond special.
"She was a gift from god & a gift to us as someone to admire, inspire and forever miss."
Tributes to 'Granny Nancy' again poured in on Louise's Facebook page, with one person writing "She was an amazing woman and I enjoyed getting to know her through you. Hope you stay on Facebook and we get to know more about you".
Another wrote: "My heart goes out to you Louise it's so hard to say goodbye , Nancy was everyones Granny, she was full of life and made us all feel better with her infectious smile, her warm words, I just loved that smile, it would fill my heart.
"You will never be forgotten Nancy and you will live forever in my heart."
You can follow updates from Louise on her Facebook page here.