Maria Montessori was raised Catholic but turned to Eastern theosophy. As a young woman, she was involved in feminism and focused on altering the relationship of women within the family. This would apparently be a result of the Theosophy Society of which she was a member. Maria neither cared for her child nor directed her child's education. Instead, she spent her time attempting to educate the mentally ill. Her involvement in theosophy formed her educational methods as well as her understanding of God and religion.
In 1870 Maria Montessori was born into an Italian Catholic family. Many theosophists claim that at a young age she was involved in the Theosophy Society, which would explain her strong views on feminism. During "first-wave feminism," English women were frequently joining the Theosophical Society in great numbers. Montessori desired a higher education, and she studied for a doctorate by joining a boys-only school. She often spoke out against the Biblical understanding of motherhood and the role of the family.
“the woman of the future will have equal rights as well as equal duties…Family life as we know it may change, but it is absurd to think the feminism will destroy maternal feelings. The new woman will marry and have children out of choice, not because matrimony and maternity are imposed on her.” Maria Montessori https://thenewinquiry.com/blog/dr-maria-montessori-feminist/
This concept that women will not marry and have children because matrimony and maternity are imposed on them, is a concept utterly foreign to Catholicism. Catholic teaching is clear that children are the fruit of marriage, as well as its primary end. This was reinforced by a formal declaration during the pontificate of Pius XII. Montessori rejected the moral obligation of both husbands and wives to carry out God's command in Genesis to be fertile and multiply.
"Maria often found herself at odds with many of the teachings of the Catholic Church." Scottie May https://www.biola.edu/talbot/ce20/database/maria-montessori
Eventually, Maria Montessori would have a child with a fellow doctor who was co-director with her in the Orthophrenic School in Rome. Presuming that upon marrying, she would be expected to give up her career, Maria choose to continue with her work. Rather than being burdened with caring for her son, she placed him in foster care and continued her professional career.
Eventually, Maria Montessori began working with mentally disabled children. It was through her role as a teacher that she would begin to implement her understanding of theosophy into her method of education. She eventually started a school called Casa dei Bambini, which was the beginning of her fame. The school was spoken about highly by her friend Annie Besant, the famous theosophist.
"MARIA MONTESSORI had her first acquaintance with theosophy, early in the twentieth century, when she went to hear Annie Besant speak in London in 1907 after Montessori had established her first Casa dei Bambini(i.e., Children's House). Annie Besant spoke in praise of Montessori's work in education which pleased Montessori, and thus sealed their friendship." Winifred Wylie https://www.theosophical.org/publications/quest-magazine/42-publications/quest-magazine/1409-montessori-and-the-theosophical-society
Though she was not vocal about her membership in the theosophy society, she had officially joined in 1899.
“Following her death in 1952, the Society President, C. Jinarajadasa, reported that Maria Montessori did in fact join the Theosophical Society on May 23, 1899. Her original application had been found by the Recording Secretary's Office at Adyar. There being no Italian Section the time, Montessori joined the European Section and was admitted by the General Secretary, Mr Otway Cuffe. Her membership was later dropped. …...Montessori gave full voice to the spirituality which had always been in her work....couched in language appreciated by the Theosophical Community. Journal of Theosophy ; The Montessori Method was published in 1912 and much of her work was published by the Theosophical Publishing House.” 
Montessori did receive a blessing from Pope Benedict XV, however, she was highly criticized by the Jesuits, and revered by many as a liberal.
In time, Maria left Europe for India where her involvement in theosophy would become her vocation. It was here that she wrote for the Theosophy Society Journal; it was also here that her involvement with the occult would become publically manifest. Not only is Montessori's ideology characterized by the error of Modernism; it is also riven with the error of religious indifferentism.
“Just as language has many: English, Swedish, Swahili, and so forth, so does elevation express itself by way of different creeds: Christianity, Judaism, Buddhism and many different belief systems in order to communicate with and about god." Maria Montessori https://www.crossroad.to/Q&A/education/Montessori.htm
Theosophy proposes a radically novel understanding of religion, which eschews on a system of belief in favor of looking for truths in all the different creeds available. In many regards, the kind of feminism in which Maria was involved was a sort of religious feminism. During the first development of feminism, the Theosophy Society participated heavily, but not under their own name, under the banner of Freemasonry. It is clear that the philosophical foundation of the Montessori Method, and therefore Catechesis of the Good Shepherd, lies in Eastern syncretic thought, radical feminism, and anti-Catholic Freemasonry.
Various Montessori publications, such as "The Child: The Eternal Messiah", show the ideology of theosophy permeating the Montessori Method which is at the heart of Catechesis of the Good Shepherd. Theosophy, therefore, affects the entire teaching method of Catechesis of the Good Shepherd Program. The authors of Catechesis of the Good Shepherd, disciples of Montessori, produced a system that teaches different faiths and presents them all as equally valid. Apparently, they held to the theosophical concept that no religion is perfect, and all religions contain bits of truth.
Ecumenism is not just a branch of catechesis; rather, the spirit of ecumenism does permeate the whole of catechesis. (p. 123 Religious Potential of the Child, 6-12 years)
 Dixon 2001, p. 6.
 History of Education Society Bulletin (1985) vol 36 pp53-54