Where a testamentary disposition is made upon a condition precedent, nothing vests until the condition is fulfilled except where such fulfillment is impossible, in which case the disposition vests, unless the condition was the sole motive thereof, and the impossibility was unknown to the testator, or arose from an unavoidable event subsequent to the execution of the will. R.L. 1910, Sec. 8411. R.L.1910, § 8334.
Oklahoma Legal Code