es ▁began ▁his ▁career ▁as ▁a ▁commander ▁of ▁one ▁of ▁the ▁western ▁tag m ata ▁during ▁the ▁reign ▁of ▁Bas il ▁II ▁( r . ▁ 9 7 6 – 1 0 2 5 ), ▁in ▁the ▁latter ' s ▁campaign s ▁against ▁Bulg aria . ▁In ▁ 1 0 1 4 , ▁he ▁participated ▁in ▁the ▁decis ive ▁By z antine ▁victory ▁at ▁the ▁Battle ▁of ▁Kle id ion ▁( J uly ▁ 2 9 ), ▁and ▁he ▁subsequently ▁succeeded ▁The oph y la ct ▁Bot ane i ates ▁as ▁commander ▁( d oux ) ▁of ▁Th ess al onica ▁with ▁the ▁rank ▁of ▁patri ki os , ▁making ▁him ▁the ▁second - most ▁senior ▁general ▁of ▁the ▁Empire ▁in ▁the ▁B alk ans ▁after ▁David ▁A rian ites . ▁Following ▁the ▁death ▁of ▁Ts ar ▁Samuel ▁of ▁Bulg aria ▁in ▁October , ▁Di ogen es ▁and ▁N ike ph or os ▁X i phi as ▁were ▁dispatch ed ▁to ▁the ▁region ▁of ▁M og l ena ▁as ▁the ▁v angu ard ▁of ▁the ▁em peror ▁and ▁the ▁main ▁army . ▁During ▁this ▁campaign , ▁Di ogen es ▁constructed ▁the ▁for tr ess ▁of ▁My lob os , ▁as ▁att ested ▁in ▁a ▁founder ' s ▁ins cription . ▁ ▁The ▁con quest ▁of ▁M og l ena ▁was ▁completed ▁in ▁ 1 0 1 5 ▁or ▁ 1 0 1 6 . ▁In ▁ 1 0 1 7 , ▁Di ogen es ▁and ▁David ▁A rian ites ▁led ▁troops ▁to ▁pl