Popular yoga teacher BKS Iyengar died two weeks ago at the age of 96. Iyengar was hospitalized after an illness that left him short of breath. He passed away in the presence of his family. Writing on Twitter, students and admirers around the world have expressed grief about Iyengar's death and gratitude for his many years of work.

Iyengar is considered one of the key people to popularize the Hatha Yoga, both inside India and well beyond its borders. “Hatha” Yoga seeks to “bring balance between the sun and the moon” in people who practice it. Bellur Krishnamachar Sundararaja Iyengar, or “BKS Iyengar” for short, was introduced to yoga in 1935 by his brother-in-law at the age of sixteen. Later, when Iyengar became a yoga instructor, the musician Yehudi Menuhin invited him teach outside India, launching Iyengar’s career as a yoga instructor in the West. He went on to teach thousands of students and author 14 books on yoga.

Iyengar even developed a form of Hatha Yoga now called Iyengar Yoga, which emphasizes detail, precision, and alignment in the performance of posture and breath control. Carrie Owerko, one of Iyengar's students, credits him with making yoga more accessible to everyone, whatever their physical or mental limitations. “Iyengar is a lot of the yoga people experience in the United States. The teacher may not be teaching Iyengar, but that teacher has been influenced by Iyengar yoga in some way,” she says.

Iyengar was awarded the three highest civilian awards in India: the Padma Shri in 1991, the Padma Bhushan in 2002, and the Padma Vibhushan in 2014. Time magazine also named him one of the 100 most influential people in the world in 2014.

The morning Iyengar died, India’s Prime Minister Narendra Modi expressed his grief on Twitter. Modi is known to practice yoga, which he says helps him maintain his strenuous work schedule.

I am deeply saddened to know about Yogacharya BKS Iyengar's demise & offer my condolences to his followers all over the world.

— Narendra Modi (@narendramodi) August 20, 2014

Journalist and television presenter Shaili Chopra tweeted her tribute with a tongue-in-cheek image to illustrate Iyengar’s influence on the teaching of yoga in the world. The image alters the word “asana” (a posture adopted in performing Hatha Yoga) to “aasaan,” which means “easy” in Hindi. Thus, the image declares how Iyengar made yoga “easy.”

“@nivedithalva: #iyengar – #Amul does it so well ! RIP pic.twitter.com/W5dc5YuhWw”

— Shaili Chopra (@shailichopra) August 26, 2014

Those mourning the loss of Iyengar have ranged from famous athletes to ordinary Internet users. Indian cricket star Sachin Tendulkar also paid tribute, saying that the asanas he learned under Iyengar helped him throughout his athletic career. Other yoga practitioners expressed their gratitude to Iyengar and their grief at hearing of his passing.

I sit in deep silence w/ tears of gratitude streaming down my face that #yoga crossed my path this lifetime. #Iyengar pic.twitter.com/ohYnwIoctX

— Ashley Turner (@AshleyTurner1) August 20, 2014

Elizabeth Kadetsky, a student of Iyengar, who has also written a book about her time with him, tweeted:

BKS–very sad and feeling your spirit really fly through here #bksiyengar

— Elizabeth Kadetsky (@ekadetsky) August 20, 2014

The Manchester and District Institute of Iyengar Yoga, which offers yoga classes and aims to promote the understanding and practice of Iyengar Yoga, is planning a book featuring tributes to him.

We are creating a book of your reflections and condolences so please continue to send them if you wish. #BKSIyengar pic.twitter.com/KtRIo6rfiV

— Iyengar Yoga (@MDIIY) August 23, 2014

Thousands who have benefited from Iyengar's work have been unable to visit mourning sites to offer their tributes and condolences in person. Online social media, however, offer these people a powerful medium to express their grief and gratitude. The hashtag #Iyengar is still trending now, buzzing with pictures of Iyengar and famous things he said. Indeed, nothing less could be expected for a man with such a legacy.