Iowa State and Iowa announced Wednesday the two schools have agreed to extend the Cy-Hawk Series through the 2021 football season.

The four-year extension of the series will kick in following the 2017 football season, when the current contract expires. The Cyclones will play in Iowa City in the 2018 and 2020 seasons of the new contract while Iowa will travel to Ames to play during the 2019 and 2021 seasons.

Following a 43-year span without playing each other in the series, Iowa and Iowa State resumed the series in 1977. The Hawkeyes lead the all-time series 40-21 following this season’s 27-21 victory at Jack Trice Stadium.

“We are excited to extend our contract with the University of Iowa in football through the 2021 season,” ISU Athletics Director Jamie Pollard said Wednesday in a news release. “This game is very important to the residents of this state and I am pleased both institutions are committed to continuing the rivalry. Rivalry games are great for college football.”