at first
WordReference English Thesaurus © 2020
in the beginning, initially , firstly , in the first place, at the outset, at the start, at the beginning, at the commencement, originally , first off, for openers, to start with, to begin with, from the off (slang)

'at first' also found in these entries (note: many are not synonyms or translations):

Report an inappropriate ad.