See Ambatthala. Geiger thinks (Mhv. Trs.264, n.3) that Therambatthala is the name given to the Ambatthalathúpa, built (on the Cetiyagiri) by Mahádáthika Mahánága in memory of Mahinda.
But, probably, the whole of this locality later came to be referred to by this name, for Therambatthala is mentioned (Vsm.155, 375; DhSA 187) as the residence of monks, among them, Buddha-Rakkhita and Mahá-Rohanagutta.