The eighth Shi'ite Imam, Imam Ali ibne Musa al-Rida (A.S.) is also called as Imam-e-Zaamin (A.S.). When Muslims go on journeys they take with them something called Imam-e-Zaamin (another name for Imam Rida (A.S.)) which is some money tied in a cloth. This tradition probably came from the time of Imam Rida (A.S.) when people used to carry money with them especially because it had Holy Imam's (A.S.) name on it. As Ma'mun,the Abbasid caliph the contemporary of Imam Rida (A.S.), had coins minted with the name of Imam Rida (A.S.) on them, it was very easy for the Muslims to carry the name of Holy Imam (A.S.) with them, especially when they went on journeys.
Imam Rida (A.S.) is also known as "Imam-e- Zaamin (A.S.)". Zaamin means "The Guarantor". One day when Imam Rida (A.S.) was on his historical journey from Madinah to Marw(Khurasan),while in a jungle the Holy Imam (A.S.) came across a hunter who was about to kill a deer. The deer was trying to get away and when she saw Holy Imam (A.S.), she said something to him. Holy Imam (A.S.) asked the hunter to free the deer so that she could go and feed her little baby deer who were very hungry. Imam Rida (A.S.) also told the hunter that once the deer had fed her babies she would come back. The hunter allowed the deer to go because Holy Imam (A.S.) had told him to, but he did not think the deer will come back. But Imam Rida (A.S.)) waited with the hunter until the deer returned with her young ones. The hunter was amazed on witnessing this miraculous event and he set the deer free as a mark of respect for Imam Rida (A.S.).After this historical event Imam Rida (A.S.) became famous as Imam Zaamin (A.S.).
* The most famous artist of the contemporary world, Ustad Mahmud Farshchiyan has depicted this historical event in this beautiful masterpiece iconograph entitled "Zaamin-e-Aahu"(The Guarantor of the Deer).