Arsenal defender Shkodran Mustafi admits he left Valencia because of Arsene Wenger.
Mustafi appreciates the stability the Gunners offer.
"Sometimes you do not know how good a coach is if you're not training with him on a day-to-day basis," Mustafi said.
"He (Wenger) is the head of Arsenal and it was important when choosing the Arsenal, because he's been a long time here and has made a very solid club structure.
"When I was with Valencia and before in Sampdoria there were a lot of coach changes, every 12 months, and that raises doubts because with the new coach different ideas come, different types of football ..."