Short answers, pulled from the story.
A dispensation is a temporary suspension of a law's immediate obligation granted by the Catholic Church when strict adherence would cause greater harm than good. This mechanism allows the Church to set aside its own rules in specific cases without creating a permanent right or special privilege for an individual. The exemption vanishes if the reason for granting it disappears, ensuring the law remains the default standard for the community.
The Council of Trent convened in the mid-16th century to establish modern dispensation practices within the Roman Catholic Church. The Council decreed that all dispensations must be issued only for just and urgent causes or for a decided benefit to the Church. It also mandated that these dispensations be granted for free, voiding any dispensation where money was exchanged for the exemption.
In 1908, Pope Pius X reorganized the Roman Curia through the apostolic constitution Sapienti to centralize dispensing power. This reform transferred dispensing power from the Dataria and Penitentiaria to the newly established Congregatio de Disciplinâ Sacramentorum. The reorganization streamlined the handling of matrimonial dispensations involving public impediments and matters of faith.
Diocesan bishops possess significant dispensing powers by virtue of their jurisdiction to dispense from impediments not reserved to the Pope. They can dispense from diriment impediments through tacit consent of the Holy See in the internal forum for secret impediments or through specific urgent circumstances. In 1888, a decree from the Congregation of the Inquisition granted bishops the power to dispense from all diriment impediments of ecclesiastical law in cases of real danger of death.
The Council of Trent decreed that dispensations should be free of all charges, yet petitioners must bear various costs in the Roman Curia. Expenses fall into four categories including carriage expenses, a tax to defray Holy See expenses, a fine called the componendum, and an alms imposed on petitioners. The Innocentian Tax approved by Pope Innocent XI on the 8th of October 1678 sanctions only modest contributions to chancery expenses for diocesan chanceries.