RIVADULLA DURÓ v. SPAIN DECISION v. France (dec.), no. 25239/13, § 30, ECHR 2015 (extracts), with further references)”. In the present case, the domestic courts’ assessment also took into account the experience of the Spanish population with regard to previous acts of terrorism carried out by ETA and GRAPO (see, mutatis mutandis, Williamson v. Germany (dec.), no. 64496/17, § 27, 8 January 2019). 38. The Court concludes that the national courts, in convicting the applicant, took care to assess his guilt on the basis of the criteria defined by the Court’s case-law, having regard to the requirements of Article 10 § 2 of the Convention, and after weighing up the various interests involved. The Court sees no serious reason to substitute its own assessment for that of the national authorities, emphasising the importance, in a case such as this one, of the reasoning of the national courts (see Williamson, cited above, § 23). 39. The grounds on which the applicant’s conviction was based, namely combating public praise or justification of terrorism, appear to be both “relevant” and “sufficient” to justify the interference at issue, and in that sense met a pressing social need (see Z.B. v. France, cited above, §§ 65-66, and, mutatis mutandis, ROJ TV A/S v. Denmark (dec.), no. 24683/14, § 47, 17 April 2018, and Pastörs v. Germany, no. 55225/14, § 48, 3 October 2019). 40. Lastly, an assessment of the nature and severity of the sanctions should be carried out to ascertain whether the interference was proportionate. In the context of Article 10 of the Convention, a criminal conviction constitutes one of the most serious forms of interference with the right to freedom of expression (see Z.B. v. France, cited above, § 67, and Reichman v. France, no. 50147/11, § 73, 12 July 2016). 41. In the present case, the sentence of two years’ imprisonment imposed on the applicant was reduced to nine months on appeal. The Court further notes that the applicant had already received a suspended prison sentence for a previous offence of glorification of terrorism (see paragraph 15 above). The Court considers that without that sentence, the applicant’s conviction in the present case would not have resulted in his being imprisoned. His imprisonment was the consequence of his successive convictions. The Court concludes that the applicant’s criminal conviction and sentence in the present case cannot be considered disproportionate to the legitimate aim pursued. 42. In the light of the foregoing, the Court considers that the complaint under Article 10 of the Convention is manifestly ill-founded within the meaning of Article 35 § 3 (a) and must be rejected pursuant to Article 35 § 4 of the Convention. 2. Conviction for slander against the Head of State and the State institutions 43. Referring to the applicant’s convictions for slander against the Head of State and the State institutions (see paragraphs 9 and 11 above), the Court notes that both convictions constituted an interference with the applicant’s 14