This inscription is dated by two different eras; the 'year of the lord of kings' is the Seleucid era, and the 'year of the people of Tyre' is a local era, which therefore must have begun in 275/4 B.C. In that year the First Syrian War began, and Tyre probably achieved some form of autonomy as a result.
The translation is taken from G.A. Cooke, "A Text-book of North-Semitic Inscriptions", no. 9 ( archive.org ).
To the lord Baʿal-shamem this is that which ʿAbd-elim, son of Mattan, son of ʿAbd-elim, son of Baʿal-shamar, in the district of Laodicaea, vowed : - even this gate and the doors thereof I made in fulfilment of it (?); I built this in the year 180 of the lord of kings, the 143rd year of the people of Tyre, that it may be to me for a memorial and a good name under the foot of my lord Baʿal-shamem for ever: may he bless me !
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