[ummwhat]

At the point where all the people involved are dead because the world belongs to the living. About 100 years is enough.

[lupire]

The descendants are involved. The deaths of ancestors has an effect on the descendants.

Also, gauge theory suggests that someone who thinks assassination was cool in 1600 would also think that assassination is cool in 2000.

[z3phyr]

Their death directly lead to the other events which lead to other events. You can always blame the fate if death was natural, but if some other party was involved, that party directly played god with their actions and ruined someone else's life trajectory and thus their descendants life trajectory. And now you find out that the descendants of the murderers are proud of their heritage and hero worship at the expanse of you.

[eigenloss]

Turkey is doing almost the exact same atrocities today under Erdogan that they did in the 1920s under Ataturk.