Look, make yourself a gift of this present time. Those who are more inclined to pursue fame hereafter fail to reckon that the next generation will have people just like those they dislike now: and they too will die. What, anyway, is it to you if this is the echo in future voices and this the judgement they make of you?
Life is opinion. I believe that many think the way to contentment and joy is through money, fame, ease, pleasure or something similar. For Marcus, joy meant being constant and unaffected by the desires and externals that surround and bombard us. To keep his "directing mind" pure from wanting these externals by perpetually exercising the discipline of assent (breaking everything down and seeing things for what they are). Furthermore, he simply wanted to be kinds to others and mete out justice as they deserved.
Be content with the present and avoid the anxiety of trying to be remembered. So many wan to "make their mark in life" and Marcus rightly points out that any mark made by someone in this life will soon fade. Politics, culture, fashion ... all of it is an endless cycle and never stops changing. If you do "make a mark" in this life, more likely someone will come along and think that "mark" wasn't so great to begin with and will go about to overwrite it. Conclusion: live your life in justice with those that share this time and space with you. Don't ever be anxious about lack of fame, fortune or pleasure. It's all vanity.
(see also Citadel p. 216)