Countering a concentration spell while concentrating on darkness

combatconcentrationdnd-5espellcastingspells

I had a recent rules argument with a couple of fellow players during a spellcasting tournament. I'm a warlock/monk with the concentration spells silence and darkness, as well as the devil's sight invocation. I was standing in my magical darkness completely unseen, and cast silence on a space including both other contenders who were unable to move. They didn't have any counterspells left so it wouldn't have affected the outcome, but one of the players wanted to know if they could have counterspelled the silence, considering that I was in darkness when I began casting. I don't rightly know, so I'm interested to know if someone could have countered my silence.

Best Answer

Yes, they can

Casting another spell that requires concentration. You lose concentration on a spell if you cast another spell that requires concentration. You can't concentrate on two spells at once.

When you start casting Silence, that breaks your concentration on Darkness. At that point, they can see and Counterspell you.