Question: When did the party of Oklahoma's US Senators take control of the body determining the rules of the US House and US Senate?

Knowledge 1: Oklahoma
Following the 2000 census, the Oklahoma delegation to the U.S. House of Representatives was reduced from six to five representatives, each serving one congressional district. For the 112th Congress (2011–2013), there were no changes in party strength, and the delegation included four Republicans and one Democrat. In the 112th Congress, Oklahoma's U.S. senators were Republicans Jim Inhofe and Tom Coburn, and its U.S. Representatives were John Sullivan (R-OK-1), Dan Boren (D-OK-2), Frank D. Lucas (R-OK-3), Tom Cole (R-OK-4), and James Lankford (R-OK-5). [SEP] Knowledge 2: Standing Rules of the United States Senate
The Standing Rules of the Senate are the parliamentary procedures adopted by the United States Senate that govern its procedure. The Senate's power to establish rules derives from Article One, Section 5 of the United States Constitution: ``Each House may determine the rules of its proceedings... '' [SEP] Knowledge 3: 2014 United States Senate elections
The Republicans regained the majority of the Senate in the 114th Congress, which started in January 2015; the Republicans had not controlled the Senate since January 2007. They had needed a net gain of at least six seats to obtain a majority. They held all of their seats, and gained nine Democratic - held seats. Republicans defeated five Democratic incumbents:
Knowledge 1: Oklahoma
Following the 2000 census, the Oklahoma delegation to the U.S. House of Representatives was reduced from six to five representatives, each serving one congressional district. For the 112th Congress (2011–2013), there were no changes in party strength, and the delegation included four Republicans and one Democrat. In the 112th Congress, Oklahoma's U.S. senators were Republicans Jim Inhofe and Tom Coburn, and its U.S. Representatives were John Sullivan (R-OK-1), Dan Boren (D-OK-2), Frank D. Lucas (R-OK-3), Tom Cole (R-OK-4), and James Lankford (R-OK-5). [SEP] Knowledge 2: Standing Rules of the United States Senate
The Standing Rules of the Senate are the parliamentary procedures adopted by the United States Senate that govern its procedure. The Senate's power to establish rules derives from Article One, Section 5 of the United States Constitution: ``Each House may determine the rules of its proceedings... '' [SEP] Knowledge 3: 114th United States Congress
The One Hundred Fourteenth United States Congress was a meeting of the legislative branch of the United States federal government, composed of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from January 3, 2015, to January 3, 2017, during the final two full years of Barack Obama's presidency. The 2014 elections gave the Republicans control of the Senate (and control of both houses of Congress) for the first time since the 109th Congress. With 248 seats in the House of Representatives and 54 seats in the Senate, this Congress began with the largest Republican majority since the 71st Congress of 1929 -- 1931.
Knowledge 1: Oklahoma
Following the 2000 census, the Oklahoma delegation to the U.S. House of Representatives was reduced from six to five representatives, each serving one congressional district. For the 112th Congress (2011–2013), there were no changes in party strength, and the delegation included four Republicans and one Democrat. In the 112th Congress, Oklahoma's U.S. senators were Republicans Jim Inhofe and Tom Coburn, and its U.S. Representatives were John Sullivan (R-OK-1), Dan Boren (D-OK-2), Frank D. Lucas (R-OK-3), Tom Cole (R-OK-4), and James Lankford (R-OK-5). [SEP] Knowledge 2: 114th United States Congress
The One Hundred Fourteenth United States Congress was a meeting of the legislative branch of the United States federal government, composed of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from January 3, 2015, to January 3, 2017, during the final two full years of Barack Obama's presidency. The 2014 elections gave the Republicans control of the Senate (and control of both houses of Congress) for the first time since the 109th Congress. With 248 seats in the House of Representatives and 54 seats in the Senate, this Congress began with the largest Republican majority since the 71st Congress of 1929 -- 1931. [SEP] Knowledge 3: 2014 United States Senate elections
The Republicans regained the majority of the Senate in the 114th Congress, which started in January 2015; the Republicans had not controlled the Senate since January 2007. They had needed a net gain of at least six seats to obtain a majority. They held all of their seats, and gained nine Democratic - held seats. Republicans defeated five Democratic incumbents:

Answer: January 2015