I connected an LED in series with the capacitor (any type of capacitor. I used one of 10 μF) and connected them with the 9V DC battery. I connected the positive pin of the capacitor directly to the positive side of the battery and attached the positive pin of the LED with the negative pin of the capacitor (as the LED and the capacitor are in series combination) and connected the negative pin of the LED to the negative side of the battery. So, The bulb should gradually turn dim and then turn off and it did. I followed a diagram of the circuit but I cant attach it with the question due to the lack of population.

My question is, why does this happen? Why does the light turn dim when attached to a capacitor in series?

I am quite new in electronics. Therefore I am not quite familiar with the complex detailed descriptions but still I am trying to give as much details as possible. Pardon me if there has been any mistakes in my question.