Okla. Stat. tit. 84, § 84-181: Condition precedent must be fulfilled - Exception

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.