Section XII-A-1: Exemption from ad valorem taxation authorized.

  All homesteads as is or may be defined under the Laws of the
State of Oklahoma for tax exemption purposes, may hereafter be
exempted from all forms of ad valorem taxation by the
Legislature; provided, that all assessments, levies, encumbrances
and other contract obligations incurred or made prior to the
taking effect of such act of the Legislature shall in no way be
affected or impaired by the exercise of Legislative power as
authorized by this amendment.