1) Ancient 2) Ancient as the hills 3) Antediluvian 4) Antique 5) Ancient 6) Belonging to an ancient time 7) Classic 8) Dating from time immemorial 9) Drenched 10) From ancient times 11) From long, long ago 12) From time immemorial 13) From times of yore 14) From way back 15) From way back when 16) Going back 
[adj] - belonging to or lasting from times long ago
adjective belonging to or lasting from times long ago; `age-old customs`; `the antique fear that days would dwindle away to complete darkness`
ancient; from time immemorial: an age-old tradition.