Mirra Alfassa, also known as The Mother, played a crucial role in the development of the Integral Yoga alongside Sri Aurobindo. Her spiritual collaboration with Sri Aurobindo was based on their shared vision of a spiritual evolution that would lead to a higher consciousness and a more harmonious world.

The Integral Yoga, also known as the Supramental Yoga, was a synthesis of various yogic practices and philosophies, including the traditional Indian Yoga, Western esotericism, and modern psychology. It aimed to integrate all aspects of an individual's being - physical, vital, mental, and spiritual - to achieve a complete transformation and a higher state of consciousness.

Mirra Alfassa's role in the development of the Integral Yoga was multifaceted. She was not only a spiritual collaborator but also a guide, teacher, and embodiment of the yogic principles. Her deep spiritual experiences and intuitive understanding of the human psyche were instrumental in shaping the Integral Yoga.

One of her significant contributions was her work on the physical transformation of the body, which she called the "supramentalisation." She believed that the human body could be transformed into a more evolved and conscious state, which would be the foundation for the next stage of human evolution. Through her own experiences and experiments, she developed specific practices and techniques to facilitate this transformation.

Mirra Alfassa also played a crucial role in the establishment of the Sri Aurobindo Ashram and the Auroville community, which were the physical manifestations of the Integral Yoga. She provided guidance and support to the members of the ashram and Auroville, encouraging them to live a life of conscious evolution and unity.

Furthermore, she emphasized the importance of an individual's inner development and spiritual growth as the key to a harmonious and peaceful world. She believed that the transformation of the individual would eventually lead to the transformation of society and the world.

In conclusion, Mirra Alfassa's role in the development of the Integral Yoga was essential and multifaceted. Her spiritual collaboration with Sri Aurobindo, her work on the physical transformation of the body, and her guidance and support to the members of the ashram and Auroville were all crucial in shaping the Integral Yoga and its principles. Her vision and teachings continue to inspire and guide spiritual seekers on the path of conscious evolution.