ABBAS I. (e. 1557-1628 or 1629), shah of Persia, called the Great, was the son of shah Mahommed (d. 1586) . In the midst of general anarchy in Persia, he was proclaimed ruler of Khorasan, and obtained possession of the Persian throne in 1586. Determined to raise the fallen fortunes of his country, he first directed his efforts against the predatory Uzbegs, who occupied and harassed Khorasan. After a long and severe struggle, he regained Meshed, defeated them in a great battle near Herat in 1597, and drove them out of his dominions. In the wars he carried on with the Turks during nearly the whole of his reign, his successes were numerous, and he acquired, or regained, a large extent of territory. By the victory he gained at Bassora in 1605 he extended his empire beyond the Euphrates; sultan Ahmed I. was forced to cede Shirvan and Kurdistan in 1611; the united armies of the Turks and Tatars were completely defeated near Sultanieh in 1618, and Abbas made peace on very favourable terms; and on the Turks renewing the war, Bagdad fell into his hands after a year's siege in 1623. In 1622 he took the island of Ormuz from the Portuguese, by the assistance of the British, and much of its trade was diverted to the town of Bander-Abbasi, which was named after the shah. When he died, his dominions reached from the Tigris to the Indus. Abbas distinguished himself, not only by his successes in arms, and by the magnificence of his court and of the buildings which he erected, but also by his reforms in the administration of his kingdom. He encouraged commerce, and, by constructing highways and building bridges, did much to facilitate it. To foreigners, especially Christians, he showed a spirit of tolerance; two Englishmen, Sir Anthony and Sir Robert Shirley, or Sherley, were admitted to his confidence. His fame is tarnished, however, by numerous deeds of tyranny and cruelty. His own family, especially, suffered from his fits of jealousy; his eldest son was slain, and the eyes of his other children were put out, by his orders.

See The Three Brothers, or Travels of Sir Anthony, Sir Robert Sherley, &c. (London, 1823); Sir C. R. Markham, General Sketch of the History of Persia (London, 1874).

ABBASIDS, the name generally given to the caliphs of Bagdad, the second of the two great dynasties of the Mahommedan empire. The Abbasid caliphs officially based their claim to the throne on their descent from Abbas (A.D. 566-652), the eldest uncle of Mahomet, in virtue of which descent they regarded themselves as the rightful heirs of the Prophet as opposed to the Omayyads, the descendants of Omayya. Throughout the second period of the Omayyads, representatives of this family were among their most dangerous opponents, partly by the skill with which they undermined the reputation of the reigning princes by accusations against their orthodoxy, their moral character and their administration in general, and partly by their cunning manipulation of internecine jealousies among the Arabic and non-Arabic subjects of the empire. In the reign of Merwan II. this opposition culminated in the rebellion of Ibrahim the Imam, the fourth in descent from Abbas, who, supported hy the province of Khorasan, achieved considerable successes, but was captured (A.D. 747) and died in prison (as some hold, assassinated). The quarrel was taken up by his brother Abdallah, known by the name of Abu'l-Abbas as-Saffah, who after a decisive victory on the Greater Zab (750) finally crushed the Omayyads and was proclaimed caliph.

The history of the new dynasty is marked by perpetual strife and the development of luxury and the liberal arts, in place of the old-fashioned austerity of thought and manners. Mansur, the second of the house, who transferred the seat of government to Bagdad, fought successfully against the peoples of Asia Minor, and the reigns of Harun al-Rashid (786--809) and Mamun (813-833) were periods of extraordinary splendour. But the empire as a whole stagnated and then decayed rapidly. Independent monarchs established themselves in Africa and Khorasan (Spain had remained Omayyad throughout), and in the north-west the Greeks successfully encroached. The ruin of the dynasty came, however, from those Turkish slaves who were constituted as a royal bodyguard by Moqtasim (833-842). Their power steadily grew until Radi (934-941) was constrained to hand over most of the royal functions to Mahommed b. Raik. Province after province renounced the authority of the caliphs, who were merely lay figures, and finally Hulagu, the Mongol chief, burned Bagdad (Feb. 28th, 1258). The Abbasids still maintained a feeble show of authority, confined to religious matters, in Egypt under the Mamelukes, but the dynasty finally disappeared with Motawakkil III., who was carried away as a prisoner to Constantinople by Selim I.

See CALIPHATE (Sections B, 14 and C), where a detailed account of the dynasty will be found.

ABBAS MIRZA (c. 1783-1833), prince of Persia, was a younger son of the shah, Feth Ali, but on account of his mother's royal birth was destined by his father to succeed him. Entrusted with the government of a part of Persia, he sought to rule it in European fashion, and employed officers to reorganize his army. He was soon at war with Russia, and his aid was eagerly solicited by both England and Napoleon, anxious to checkmate one another in the East. Preferring the friendship of France, Abbas continued the war against Russia, but his new ally could give him very little assistance, and in 1814 Persia was compelled to make a disadvantageous peace. He gained some successes during a war between Turkey and Persia which broke out in 1821, but cholera attacked his army, and a treaty was signed in 1823. His second war with Russia, which began in 1825, was attended with the same want of success as the former one, and Persia was forced to cede some territory. When peace was made in 1828 Abbas then sought to restore order in the province of Khorasan, which was nominally under Persian supremacy, and while engaged in the task died at Meshed in 1833. In 1834 his eldest son, Mahommed Mirza, succeeded Feth Ali as shah. Abbas was an intelligent prince, possessed some literary taste, and it noteworthy on account of the comparative simplicity of his life.

ABBAS-TUMAN, a spa in Russian Transcaucasia, government of Tiflis, 50 m. S.W. of the Borzhom railway station and 65 m. E. of Batum, very picturesquely situated in a cauldron-shaped valley. It has hot sulphur baths (93 1/2 deg. -118 1/2 deg. Fahr.) and an astronomical observatory (4240 ft.).

ABBAZIA, a popular summer and winter resort of Austria, in Istria, 56 m. S.E. of Trieste by rail. Pop. (1900) 2343. It is situated on the Gulf of Quarnero in a sheltered position at the foot of the Monte Maggiore (4580 ft.), and is surrounded by beautiiul woods of laurel. The average temperature is 50 deg. Fahr. in winter, and 77 deg. Fahr. in summer. The old abbey, San Giacomo della Priluca, from which the place derives its name, has been converted into a villa. Abbazia is frequented annually by about 16,000 visitors. The whole sea-coast to the north and south of Abbazia is rocky and picturesque, and contains several smaller winter-resorts. The largest of them is Lovrana (pop. 513), situated 5 m. to the south.

ABBESS (Lat. abbatissa, fem. form of abbas, abbot), the female superior of an abbey or convent of nuns. The mode of election, position, rights and authority of an abbess correspond generally with those of an abbot (q.v.). The office is elective, the choice being by the secret votes of the sisters from their own body. The abbess is solemnly admitted to her office by episcopal benediction, together with the conferring of a staff and pectoral cross, and holds for life, though liable to be deprived for misconduct. The council of Trent fixed the qualifying age at forty, with eight years of profession. Abbesses have a right to demand absolute obedience of their nuns, over whom they exercise discipline, extending even to the power of expulsion, subject, however, to the bishop. As a female an abbess is incapable of performing the spiritual functions of the priesthood belonging to an abbot. She cannot ordain, confer the veil, nor excommunicate. In England abbesses attended ecclesiastical councils, e.g. that of Becanfield in 694, where they signed before the presbyters.

By Celtic usage abbesses presided over joint-houses of monks and nuns. This custom accompanied Celtic monastic missions to France and Spain, and even to Rome itself. At a later period, A.D. 1115, Robert, the founder of Fontevraud, committed the government of the whole order, men as well as women, to a female superior.

In the German Evangelical church the title of abbess (Aebtissin) has in some cases--e.g. Itzehoe--survived to designate the heads of abbeys which since the Reformation have continued as Stifte, i.e. collegiate foundations, which provide a home and an income for unmarried ladies, generally of noble birth, called canonesses (Kanonissinen) or more usually Stiftsdamen. This office of abbess is of considerable social dignity, and is sometimes filled by princesses of the reigning houses.