Concessive clauses are clauses, where the event / action of the main clause can potentially be impeded by the action / event of the concessive clause without actually doing it.

He has no money, nevertheless he bought a car.

This is not to be confused with an adversative clause. In the case of an adversative clause the action / event of the main clause is impeded by the action / event described in the adversative clause.

He has no money and therefore he couldn' t go on holiday.

If you speak Spanish you can have a little problem concerning the use of the subjunctive / congiuntivo after concessive conjunctions.

In Spanish the concessive conjunctions are divided in two groups. To the first group belongs all the conjunctions which describes a real situation, to the second group belongs all the conjunctions which describes a hypothetical situation.

real situation
Although he has no money, he is happy.

hypothetical situation
Even if he had money, he wouldn' t be happy.

In Spanish we use in the case of a real situation the indicative. In the case of a hypothetical situation the subjunctive. This distinctions is NOT made nor in French, nor in Italian. ALL concessive conjugations requires the conjunctive / subjunctive in Italian. You may think that the Spanish system is more logical, because in Spanish only in the case of a hypothetic constellation the subjunctive is used and very likely you are right but the Italians use the congiuntivo anyway in both cases.

In the table below you find two groups, the although group, where you will find all the conjunctions which describes a real situation and the even if group, where you will find all the conjunctions that describes a hypothetical situation, but in both cases in Italian the congiuntivo / subjunctive is to be used.

group although: sebbene, benché, quantunque, nonostante (che), malgrado (che)     sebbene = although   Il Brasile è già lontano sebbene siano soltanto 5 giorni che sono arrivato qua.   The Bresil is already far away, although it is only three days ago that I arrived.   sebbene = although   Sebbene abbia solo vent'anni, Bob Dylan è uno dei più singolari cantanti folk che mai abbiano suonato a Manhattan.   Although he was only twenty years old Bob Dylan was the most outstanding folk singer who ever played in Manhatten. benchè = although   Accende una sigaretta, benché sappia che non è consigliabile farlo.   Er zündet eine Zigarette an, obwohl er weiß, dass es nicht empfehlenswert ist, dies zu tun.   quantunque = in spite of, despite   La mafia quantunque faccia sempre rumore, non è più quel dinosauro che ingoiava il progresso palermitano.   Despite all the rumours about the Mafia nowadays it isn' t the dinosaurier any more which divours the progress.   nonostante= although   Nonostante sia diventato da poco padre, non ha rinunciato al tour europeo per promuovere il suo film.   Although he had become father recently, he didn' t cancel his tour through Europe to promote his film.   malgrado = although   Keplero, malgrado fosse anche lui religioso, accettò il fatto che le orbite erano ellittiche.   Although Kepler was religious as well, he accepted the fact that the orbits can be elliptic. sebbene = although   Eppure, sebbene partiti con le migliori intenzioni, vaghiamo dapprima senza una destinazione precisa.   Although we departed with the best intentions, at the beginning we walked around without a clear destination.   Il bilancio è complesso poiché, sebbene si conoscano i fenomeni di assorbimento e di emissione della CO2, la loro interazione è difficilmente calcolabile.   The balance is complex because even if the absorption and emission of CO2 are two well studied phenomena it it difficult to make a statement about the interaction of these phenomena.   groupe else if: anche se, quantunque, seppure, con tutto che     anche se = wenn auch   La lingua Italiana non esiste a Trieste, anche se parli l'Italiano ti rispondono in dialetto e per me questo è mancanza di rispetto.   Italian doesn' t exist at Triest, even if you talk Italian with them they answer you in dialect and for me this a sign of disrespect.   Non essere timorosa anche se parli male, gli stronzi ci sono ovunque come le brave persone.   Don' t be shy even if you speak bad, there are idiots everywhere as well as nice people.   seppure = although   La frequenza, seppure non obbligatoria, è vivamente raccomandata.   The participition although not compulsory is very recommended. seppure = although   La hostess lo tranquillizza assicurandogli che, seppure ciechi, si tratta dei due più grandi piloti Italiani che esistono, e che con le moderne tecnologie a disposizione, anche un cieco può pilotare un aereo.   The stewardess tranquilize him assuring that althought they were blind they were two of greatest Italian pilots and that the modern technologies allows even to a blind to pilot an airplane.