He swore his oath of fealty to Protector Benjamin IX's grandfather, in the later half of the 19th Century PD.
He conspired with Steadholder Burdette and Brother Edmond Marchant to sabotage the Grayson Sky Domes, Ltd. project in Mueller Steading to discredit Honor Harrington. While Fitzclarence was executed for his crimes after his involvement was discovered, Mueller was able to cover up his involvement and remain untouched, though the Sword and Planetary Security continued to quietly investigate him. He even urged the Conclave to reimburse Harrington and her company for all legal costs stemming from the dome collapse, and petitioned the Protector to append the Crossed Swords to her Star of Grayson. (HH5)
Steadholder Mueller was finally impeached and executed for treason in 1916 PD, after his involvement in the Havenite-Masadan Operation Hassan, which led to the death of several high-ranking Manticoran and Grayson politicians, was discovered. (HH9)
( – 1916 PD )