All taxes which may hereafter be lawfully levied on property in this Commonwealth by any taxing district, and all taxes heretofore lawfully levied by any taxing district on any property, the lien of which has not been lost under existing laws (whether or not a claim has been filed, or return thereof has been made to the county commissioners) shall be and are hereby declared to be a first lien on said property. Such liens shall have priority to and be fully paid and satisfied out of the proceeds of any sale of said property held under the provisions of this act before any mortgage, ground rent, obligation, judgment claim, lien or estate with which the said property may have or shall become charged, or for which it may become liable, save and except only the costs of the sale and of the proceedings upon which it is made, and such tax liens of the Commonwealth of Pennsylvania given priority of payment by section 205 of this act.¹