One Side about the International Petroleum Exposition held in Tulsa in 1959.
It was the 100 year Anniversary of their founding.
It was probably the largest such  event that was ever held.
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The Other side is about the Osage Land Allotment Tribal Roll Mineral Reservation 
It was formed in 1907 & was 50 years old in 1957.
A little Osage history. The Osage Tribe signed a treaty with the US Govt. in 1825 to come to OK Territory, & the Govt agreed to Give them a large tract of Land which is now Osage County OK.
When OK Became a State in 1907, The Osage Tribe awarded allotments to Tribal members. And those members became shareholders
of any Monies rec'd by the Tribe. When oil was discovered on their land in 1920 , the Tribe became one of the richest of all Indian Tribes. And the roll members shared in this financial Income. This still goes on today.
Here is the story of how these Medals came to be made.
The man responsible was R.G. Fister, I think he worked for the Bureau of Indian Affairs for most of his adult life..
he ended his time as Supt. of the Osage Tribe from 1954/1958. 
When he retired he must have loved the Osage people so much, that he had several Medals made to honor them.
this is one of those medals. It is a silver tone metal , & he only made 100 pcs. of this medal.
It is Uncirculated , & in perfect condition . 32 MM in dia.  When Mr. Fister died, many years ago, I bought his remaining inventory of many Medals. I have not tried hard to sell them in the 40 years I have owned them. There are more and will be listed in the near future