From the time of the Tang dynasty in China (618-907), Tiantai became popular. In later centuries it declined again.
Now, a few words about Zhiyi. Although he is considered to be the fourth patriarch of this lineage, he was effectively its real founder.
He went to Tiantai Mountain, which was already a center for ascetics, to study meditation.
While there, he practiced samatha (mindful breathing) and vipassana (insight into reality) meditation.
From this training, he developed a system of Buddhist practice that included devotional rituals, and thereby made it more easily adaptable outside the Indian context.