The Maria Immaculata Statue was made by Antal Horger and was erected, according to a pledge after the black death epidemic of 1724, by the residents of Buda. Originally it was on the square which is now Batthyany ter and was moved to Irma ter in 1834, which became Maria ter after the statue. Maria ter is in the 1st district, you can easily find it by walking up on Batthyany utca from Batthyany ter (M2 underground station).