Original: He did return at least twice, the last time in A.H. 290 (903) when his outspokenness caused some uneasiness and led to his quick departure Rosenthal p. 11 .
Simplified: He did return at least twice, the last time in A.H. 290 (903) when his outspokenness caused some uneasiness and led to his quick departure  ibid p. 11 .