In 1757, Bosanquet met Sarah Crosby, who at the time was a Methodist class leader.
Meeting Crosby was the final push that Bosanquet needed to bring about her conversion to Methodism.
She then dedicated her life to the church and charity, rejecting her wealth and becoming active in the Foundry Society.
She began to visit Sarah Crosby and Sarah Ryan in the Moorfields in order to learn more about the religion.

By 1760, tensions between Bosanquet and her family had become pronounced.
Bosanquet had rejected the marriage proposal of a rich young man, which angered her parents.
Instead, she told them, she wanted to devote her life to serving God.
This, along with her rejection of wealth and her parents' fear that she would convert her brothers to Methodism, caused Bosanquet's family to ask her to leave.
She moved into unfurnished accommodation in Hoxton Square, where she soon settled in company with Sarah Ryan.

Bosanquet had something of a change of heart over her wealth in 1763.
She decided to accept it, but use it for charitable purposes.
On 24 March 1763, Bosanquet and Sarah Ryan moved to one of the Bosanquet family's properties, nicknamed 'The Cedars,' in Leytonstone.
She and Ryan felt they were called upon by God to help others.
They hoped to establish an orphanage/school modelled on John Wesley's Kingswood School.
In 1768, the school was moved to a farm named Cross Hall in Morley.

While working together at The Cedars, Bosanquet and Sarah Ryan became quite close, Ryan being like a mother to her.
Even John Wesley acknowledged their bond, calling them, "twin souls".
After Ryan's death in 1768, Bosanquet fell into a depression, her only consolation being dreams she had of Ryan still being alive.
Bosanquet's bond was so strong with Ryan that John Fletcher acknowledged Ryan as a part of their partnership during his and Bosanquet's marriage.

After marrying John Fletcher in 1781, Bosanquet decided to close Cross Hall.
She and Fletcher moved to Madeley, where they became co-pastors at a local church.

After her husband's death in 1785, Bosanquet remained in Madeley, continuing to preach.
She exercised some control over the local church hierarchy by approving curate appointments.
Bosanquet continued to do work for the Methodist Church until her death.

In 1793, Bosanquet discovered a lump in her breast, which she tried to dissolve by praying and taking goosegrass juice.
Nine months later, Bosanquet claimed the method had worked and the lump disappeared.
However, it reappeared some years later.
Further remedies were tried to unknown effect, but Bosanquet did have a lump in her breast upon her death.
In 1757, Bosanquet met Sarah Crosby, who at the time was a Methodist class leader. Meeting Crosby was the final push that Bosanquet needed to bring about her conversion to Methodism. She then dedicated her life to the church and charity, rejecting her wealth and becoming active in the Foundry Society. She began to visit Sarah Crosby and Sarah Ryan in the Moorfields in order to learn more about the religion.
By 1760, tensions between Bosanquet and her family had become pronounced. Bosanquet had rejected the marriage proposal of a rich young man, which angered her parents. Instead, she told them, she wanted to devote her life to serving God. This, along with her rejection of wealth and her parents' fear that she would convert her brothers to Methodism, caused Bosanquet's family to ask her to leave. She moved into unfurnished accommodation in Hoxton Square, where she soon settled in company with Sarah Ryan.
Bosanquet had something of a change of heart over her wealth in 1763. She decided to accept it, but use it for charitable purposes. On 24 March 1763, Bosanquet and Sarah Ryan moved to one of the Bosanquet family's properties, nicknamed 'The Cedars,' in Leytonstone. She and Ryan felt they were called upon by God to help others. They hoped to establish an orphanage/school modelled on John Wesley's Kingswood School. In 1768, the school was moved to a farm named Cross Hall in Morley.
While working together at The Cedars, Bosanquet and Sarah Ryan became quite close, Ryan being like a mother to her. Even John Wesley acknowledged their bond, calling them, "twin souls". After Ryan's death in 1768, Bosanquet fell into a depression, her only consolation being dreams she had of Ryan still being alive. Bosanquet's bond was so strong with Ryan that John Fletcher acknowledged Ryan as a part of their partnership during his and Bosanquet's marriage.
After marrying John Fletcher in 1781, Bosanquet decided to close Cross Hall. She and Fletcher moved to Madeley, where they became co-pastors at a local church.
After her husband's death in 1785, Bosanquet remained in Madeley, continuing to preach. She exercised some control over the local church hierarchy by approving curate appointments. Bosanquet continued to do work for the Methodist Church until her death.
In 1793, Bosanquet discovered a lump in her breast, which she tried to dissolve by praying and taking goosegrass juice. Nine months later, Bosanquet claimed the method had worked and the lump disappeared. However, it reappeared some years later. Further remedies were tried to unknown effect, but Bosanquet did have a lump in her breast upon her death.
Mary Bosanquet Fletcher