On the day of Ganga Sagara Mela, Sachi devi, who was residing in Jagannatha Puri, desired to bathe in the Ganges. That night the Ganges flowed from the lotus feet of Lord Jagannatha and came to Sachi’s ashrama. Entering Ganga Devi’s waters, Sachi floated to the lotus feet of Jagannatha Swami inside the Temple. After unlocking the doors the next morning the pujaris were surprised to find her inside the Temple. Thinking she was a thief, they immeditately put Sachi devi in jail. Seeing this mistake, Lord Jagannatha appeared simultaneously in a dream to both the Puri King and the head pujari. The Lord ordered them to release Sachi devi dasi and take initiation from her. From then on she became famous as Gangamata Gosvamini – See more at: http://gaudiyahistory.com/sri-gangamata-gosamini/
