What are the four unities required for joint tenancy?

Joint tenancy requires four unities: time, title, interest, and possession. Unity of time means all owners must acquire their interest at the same moment. Unity of title means all owners must receive their interest through the same deed or will. Unity of interest means all owners must hold equal shares. Unity of possession means all owners have equal right to use the entire property. If any unity is broken, the joint tenancy converts to a tenancy in common and the right of survivorship is destroyed.