What is a year dedicated to a certain saint or something else? What is a year dedicated to a certain saint or something else? Is it important?
Does it require anything in particular of Catholics?
What is a special year of a certain saint?
The response to your inquiry is very closely related to celebrating jubilees!
Every once and awhile, the pope (for the Universal Catholic Church) or a bishop (for the faithful of his particular diocese) may declare a special year dedicated to to a particular saint or Divine Mystery for a number of reasons.
During such years, the pope will outline special devotional practices in order to gain indulgences (either plenary or partial) depending on the will of the Holy Father for the particular year of dedication! As a title of example, the rules for devotional practices which could be gained for the Great Jubilee of the year 2000 can be found in this article: The Gift of the Indulgence.
The most common reason is to draw attention to an historical milestone in since the birth or death of a particular saint, or the centennial or bicentennial of some historical event or to some Divine Mystery such as the Resurrection of Our Lord Jesus Christ.

By far the most well known Jubilee Year in honour of a saint is celebrated in Santiago de Compostela whenever July 25, the day of St. James the Greater, falls on a Sunday.


The Compostela Holy Year
What it consists of and its history:
A Jubilee Year is celebrated in Santiago de Compostela whenever July 25, the day of Santiago the Elder, falls on a Sunday.
A Jubilee Year is celebrated in Santiago de Compostela whenever July 25, the day of Santiago the Elder, falls on a Sunday. This happens with a time sequence of six, five, six and eleven years. The creation of the Holy Year in Santiago goes back to the XV century. It is believed that the first one in history could have been the Jubilee Year of 1428, or perhaps 1434, both convened by Archbishop Lope de Mendoza.
However, before the Holy Year of Compostela became official, during the Middle Ages, the pilgrims could obtain numerous indulgences in Santiago, granted by the Church of Compostela in representation of the Apostle, the advocate of his pilgrims before the Supreme Judge. The indulgences are spiritual benefits for the pilgrim himself or for an ill or a deceased person represented by the pilgrim.
As from the creation of the Holy Year, the same grace could be obtained by the pilgrims who, in a normal year, visited the Cathedral on July 25, the feast day of the Passion of Santiago, or on the feast day of the Dedication of the Cathedral, every April 21, or on the feast day of the Transfer of the Body of the Apostle to Galicia, every December 30. This reduced the pressure provoked by the concentration of pilgrims on one day in summer, July 25, by convening the pilgrims in spring and winter too.
The last four Holy Years were 1993, 1999, 2004 and 2010. The next July 25 which will fall on a Sunday will be in 2021.
During all the year, the pilgrims who wish can obtain the plenary indulgence (forgiveness for their sins) during any day of that year. Achieving the plenary indulgence is what is known as the Jubilee. To do so, the pilgrims must comply with a number of precepts laid down by the Church such as visiting the Cathedral of Santiago, praying and receiving the Sacraments of Penance (Confession) and Communion.

The Cathedral of Santiago de Compostela, Spain houses the largest largest censer in the world, weighing 80 kilograms (180 lb) and measuring 1.60 metres (5.2 ft) in height.

In the Jubilee Years (whenever St James's Day falls on a Sunday) the Botafumeiro is also used in all the Pilgrims' Masses. Eight red-robed tiraboleiros pull the ropes and bring it into a swinging motion almost to the roof of the transept, reaching speeds of 80 kilometres per hour (50 mph) and dispensing thick clouds of incense.


The swinging Botafumeiro dispensing clouds of incense

Pope declares year of St. Joseph, offering special indulgences


Pope Francis on Tuesday issued a decree launching a special year dedicated to St. Joseph coinciding the anniversary of his declaration as Patron of the Catholic Church, hailing him as a model of fatherhood and a key intercessor in modern times.
Published Dec. 8, on the 150th anniversary of Quemadmodum Deus by Pope Pius IX which declared St. Joseph patron of the Catholic Church, the decree formally instituted a year for St. Joseph, which will run until Dec. 8, 2021.

These special year anniversaries usually carry with them certain indulgences accorded by the reigning pope or a bishop’s permission (with papal approval).
In the year of the Lord 1967, to commemorate the 19th centenary of the martyrdom of the Apostles Peter and Paul, a Year of Faith was proclaimed by the Pope St. Paul VI, “intended to show, by an authentic and sincere profession of the same faith, how much the essential content that for centuries has formed the heritage of all believers needs to be confirmed, understood and explored ever anew, so as to bear consistent witness in historical circumstances very different from those of the past”.
These sort of special years of commemoration are closely connected to Catholic understandings as to what constitutes a jubilee celebration.

Holy Year of Jubilee
The ultimate derivation of the word jubilee is disputed, but it is most probable that the Hebrew jobel, to which it is traced, meant &quot;a ram's horn&quot;, and that from this instrument, used in proclaiming the celebration, a certain idea of rejoicing was derived. Further, passing through the Greek iobelaios, or iobelos, the word became confused with the Latin jubilo, which means &quot;to shout&quot;, and has given us the forms jubilatio and jubilaeum, now adopted in most European languages.
Old Testament origins
For the Israelites (see HEBREW YEAR OF JUBILEE), the year of Jubilee was in any case preeminently a time of joy, the year of remission or universal pardon. &quot;Thou shalt sanctify the fiftieth year,&quot; we read in Leviticus 25:10, &quot;and shalt proclaim remission to all the inhabitants of thy land: for it is the year of jubilee.&quot; Every seventh year, like every seventh day, was always accounted holy and set aside for rest, but the year which followed seven complete cycles was to be kept as a sabbatical year of special solemnity. The Talmudists and others afterwards disputed whether the Jubilee Year was the forty-ninth or the fiftieth year, the difficulty being that in the latter case two sabbatical years must have been observed in succession. Further, there are historical data which seem to show that in the age of the Machabees the Jubilee of the fiftieth year could not have been kept, for 164-163 B.C. and 38-37 B.C. were both certainly sabbatical years, which they could not have been if two sabbatical years had been intercalated in the interval. However, the text of Leviticus (25:8-55) leaves no room for ambiguity that the fiftieth year was intended, and the institution evidently bore a close analogy with the feast of Pentecost, which was the closing day after seven weeks of harvest. In any case it is certain that the Jubilee period, as it was generally understood and adopted afterwards in the Christian Church, meant fifty and not forty-nine years; but at the same time the number fifty was not originally arrived at because it represented half a century, but because it was the number that followed seven cycles of seven.
It was, then, part of the legislation of the Old Law, whether practically adhered to or not, that each fiftieth year was to be celebrated as a jubilee year, and that at this season every household should recover its absent members, the land return to its former owners, the Hebrew slaves be set free, and debts be remitted.
The Christian jubilee
The same conception, spiritualized, forms the fundamental idea of the Christian Jubilee, though it is difficult to judge how far any sort of continuity can have existed between the two. It is commonly stated that Pope Boniface VIII instituted the first Christian Jubilee in the year 1300, and it is certain that this is the first celebration of which we have any precise record, but it is also certain that the idea of solemnizing a fiftieth anniversary was familiar to medieval writers, no doubt through their knowledge of the Bible, long before that date. The jubilee of a monk's religious profession was often kept, and probably some vague memory survived of those Roman ludi saeculares which are commemorated in the &quot;Carmen Saeculare&quot; of Horace, even though this last was commonly associated with a period of a hundred years rather than any lesser interval. But, what is most noteworthy, the number fifty was specially associated in the early thirteenth century with the idea of remission. The translation of St. Thomas of Canterbury took place in the year 1220, fifty years after his martyrdom. The sermon on that occasion was preached by Stephen Cardinal Lantron, who told his hearers that this accident was meant by Providence to recall &quot;the mystical virtue of the number fifty, which, as every reader of the sacred page is aware, is the number of remission&quot; (P.L., CXC, 421).
We might be tempted to regard this discourse as a fabrication of later date, were it not for the fact that a Latin hymn directed against the Albigenses, and certainly belonging to the early thirteenth century, speaks in exactly similar terms. The first stanza runs thus:

Anni favor jubilaei
Poenarum laxat debitum,
Post peccatorum vomitum
Et cessandi propositum.
Currant passim omnes rei.
Pro mercede regnum Dei
Levi patet expositum.

In the light of this explicit mention of a jubilee with great remissions of the penalties of sin to be obtained by full confession and purpose of amendment, it seems difficult to reject the statement of Cardinal Stefaneschi, the contemporary and counsellor of Boniface VIII, and author of a treatise on the first Jubilee (&quot;De Anno Jubileo&quot; in La Bigne, &quot;Bibliotheca Patrum&quot;, VI, 536), that the proclamation of the Jubilee owed its origin to the statements of certain aged pilgrims who persuaded Boniface that great indulgences had been granted to all pilgrims in Rome about a hundred years before. It is also noteworthy that in the Chronicle of Alberic of Three Fountains, under the year 1208 (not, be it noted 1200), we find this brief entry: &quot;It is said that this year was celebrated as the fiftieth year, or the year of jubilee and remission, in the Roman Court&quot; (Pertz, &quot;Mon. Germ. Hist.: Script.&quot; XXIII, 889). It is beyond all dispute that on 22 February, 1300, Boniface published the Bull &quot;Antiquorum fida relatio&quot;, in which, appealing vaguely the precedent of past ages, he declares that he grants afresh and renews certain &quot;great remissions and indulgences for sins&quot; which are to be obtained &quot;by visiting the city of Rome and the venerable basilica of the Prince of the Apostles&quot;. Coming to more precise detail, he specifies that he concedes &quot;not only full and copious, but the most full, pardon of all their sins&quot;, to those who fulfill certain conditions. These are, first, that being truly penitent they confess their sins, and secondly, that they visit the basilicas of St. Peter and St. Paul in Rome, at least once a day for a specified time--in the case of the inhabitants for thirty days, in the case of strangers for fifteen. No explicit mention is made of Communion, nor does the word jubilee occur in the Bull--indeed the pope speaks rather of a celebration which is to occur every hundred years--but writers both Roman and foreign described this year as annus jubileus, and the name jubilee (though others, such as the &quot;holy year&quot; or &quot;the golden year&quot; have been used as well) has been applied to such celebrations ever since. Dante, who is himself supposed by some to have visited Rome during this year to gain the Jubilee, refers to it under the name Giubbileo in the Inferno (xviii, 29) and indirectly bears witness to the enormous concourse of pilgrims by comparing the sinners passing along one of the bridges of Malebolge in opposite directions, to the throngs crossing the bridge of the Castle Sant' Angelo on their way to and from St. Peter's. Similarly, the chronicler Villani was so impressed on this occasion by the sight of the monuments of Rome and the people who flocked thither that he then and there formed the resolution of his great chronicle, in the course of which he gives a remarkable account of what he witnessed. He describes the indulgence as a full and entire remission of all sins di culpa e di pena, and he dwells upon the great contentment and good order of the people, despite the fact that during the greater part of that year there were two hundred thousand pilgrims on an average present in Rome over and above the ordinary population. With regard to the phrase just noticed, a culpa et a poena, which was often popularly used of the Jubilee and other similar indulgences, it should be observed that it means no more than what is now understood by a &quot;plenary indulgence&quot;. It implied, however, that any approved Roman confessor had faculties to absolve from reserved cases, and that the liberty thus virtually accorded of selecting a confessor was regarded as a privilege. The phrase was an unscientific one, and was not commonly used by theologians. It certainly did not mean, as some have pretended, that the indulgence of itself released from guilt as well as penalty. The guilt was remitted only in virtue of sacramental confession and the sorrow of the penitent. The sovereign pontiff never claimed any power of absolving in grievous matters apart from these. &quot;All theologians&quot;, remarks Maldonatus with truth, &quot;unanimously without a single exception, reply that an indulgence is not a remission of guilt but of the penalty.&quot; (See Paulus in &quot;Zeitschrift f. kath. Theologie&quot;, 1899, pp. 49 sqq., 423 sqq., 743 sqq., and &quot;Dublin Review&quot;, Jan., 1900, pp. 1 sqq.)

Examples of Jubilees:

Great Jubilee of the Year 2000
In 1953, with the encyclical Fulgens corona, Pope Pius ordered a Marian year for 1954, the first in Church history. It was called to commemorate the centenary of the definition of the dogma of the Immaculate Conception of the Virgin Mary.
On New Year's Day 1987, Pope John Paul II initiated a Marian year, from June 7, 1987 (Pentecost) to August 15, 1988 (the Feast of the Assumption), in preparation of the forthcoming millennium.
The Carmelites declared a Marian year in 2001 in order to deepen the Order's appreciation of its Marian heritage. Activities differed from province to province. Some held lecture series, others retreats, still others published works on the theme. In particular, there was a focus on the Brown Scapular as a sign of both the protection of Mary, and the wearer's commitment to the Carmelite charism.
In October 2016, Bishop Thomas J. Tobin announced a Marian Year for the Diocese of Providence, Rhode Island, following the close of the international Extraordinary Jubilee of Mercy in November. In recognition of the centennial anniversary of the apparitions of Our Lady of Fatima, the diocesan Office for Divine Worship participated in a pilgrimage to Portugal. A missionary image of Our Lady of Guadalupe visited parishes in the Diocese, with various presentations and holy hours.
Extraordinary Jubilee of Mercy of Pope Francis to commemorate the the closing of the Second Vatican Council.