s " ▁when ▁he ▁began ▁pre aching . ▁Most ▁sch ol ars , ▁on ▁this ▁basis , ▁assume ▁a ▁date ▁of ▁birth ▁between ▁ 6 ▁and ▁ 4   BC . ▁ ▁Three ▁details ▁have ▁been ▁used ▁to ▁estimate ▁the ▁year ▁when ▁Jesus ▁began ▁pre aching : ▁a ▁mention ▁of ▁his ▁age ▁of ▁" about ▁ 3 0   year s " ▁during ▁" the ▁fif teenth ▁year " ▁of ▁the ▁reign ▁of ▁T iber ius ▁Ca esar , ▁another ▁rel ating ▁to ▁the ▁date ▁of ▁the ▁building ▁of ▁the ▁Temple ▁in ▁Jerusalem , ▁and ▁yet ▁another ▁concerning ▁the ▁death ▁of ▁John ▁the ▁Bapt ist . ▁Hence , ▁sch ol ars ▁estimate ▁that ▁Jesus ▁began ▁pre aching ▁and ▁gather ing ▁follow ers ▁around ▁AD   2 8 – 2 9 . ▁According ▁to ▁the ▁three ▁syn opt ic ▁g osp els ▁Jesus ▁continued ▁pre aching ▁for ▁at ▁least ▁one ▁year , ▁and ▁according ▁to ▁John ▁the ▁Evangel ist ▁for ▁three ▁years . ▁ ▁Five ▁methods ▁have ▁been ▁used ▁to ▁estimate ▁the ▁date ▁of ▁the ▁cru c if ix ion ▁of ▁Jesus . ▁One ▁uses ▁non - Christ ian ▁sources ▁such ▁as ▁Joseph us ▁and ▁T ac it us . ▁Another ▁works ▁backwards ▁from ▁the ▁histor ically ▁well - est ab lished ▁trial ▁of ▁the ▁Apost le ▁Paul ▁by ▁the ▁Roman ▁pro cons ul ▁Gal lio ▁in ▁Cor inth ▁in ▁AD ▁ 5 1 / 5 2 ▁to ▁estimate ▁the ▁date ▁of ▁Paul ' s ▁conversion . ▁Both ▁methods ▁result ▁in ▁AD   3