While Gerold Hightower was obviously a very good fighter in his right own right and was described as having a stern demeanour, do you think it would have been challenging being the Lord Commander of generationally talented virtuoso’s like Arthur Dayne, Barristan Selmy, and later Jaime Lannister?
Depends on the personalities involved. Jaime was still incredibly young, and he was only a Kingsguard knight for a year or two before everyone around him died and he killed Aerys.
Gerold Hightower became Lord Commander after the tragedy of Summerhall in 259 AC, replacing Ser Duncan the Tall. A year later, Barristan Selmy joined him, aged 23. It's not clear how much older Hightower was, or when exactly he joined the Kingsguard. But I expect the two of them worked together a fair bit.
Other than Jaime, who joined at the Harrenhal tourney, we also don't have dates for the rest of the Kingsguard under Hightower's command. Arthur Dayne is described as having been Rhaegar's closest friend, which implies that he spent a significant amount of time at court, even if we can't be sure if he was in the Kingsguard the whole time. Lewyn Martell could have arrived as early as post-Summerhall (when the Princess of Dorne was lady-in-waiting to Queen Rhaella) or as late as 280 when Rhaegar married Princess Elia. Oswell Whent and Jonothor Darry, both Riverlands knights, could also have joined the Kingsguard at any time between 259 and 280, but the way they're described suggests they were pretty well established by the time Jaime arrived.
I guess much like my prior post about the Kingsguard, I hope we get more info from Barristan's POV.
