The ruler of Oman Sultan Qaboos bin Said al-Said has returned to Germany for medical tests.

Sultan Qaboos spent eight months in Germany receiving medical treatment before returning in March 2015. This trip is expected to be shorter.

“His Majesty Sultan Qaboos will today leave for Germany to continue his periodical medical check-ups, which will take a limited period of time,” said the Diwan of the Royal Court in a statement.

Sultan Qaboos’ extended treatment in Germany in 2014 caused speculation over cancer treatment and his succession plans. Since 2014, his public appearances have been limited.

The 76-year-old sultan has no sons or brothers, but several cousins. He does not plan to reveal a successor until after his death, and has not appointed any of these cousins to key government roles.