The accession of Maria Theresa to the throne of the Habsburgs Maria Theresa. marks an important epoch in the history of Austria. For a while, indeed, it seemed that the monarchy was on the point of dissolution. To the diplomacy of the 18th century the breach of a solemn compact was but lightly regarded; and Charles VI. had neglected the advice of Prince Eugene to leave an effective army of 200,000 men as a more solid guarantee of the Pragmatic Sanction than the signatures of the powers. As it was, the Austrian forces, disorganized in the long confusion of the Turkish wars, were in no condition to withstand Frederick the Great, when in 1740, at the head of the splendid army bequeathed to him by his father, he invaded Silesia (see Austrian Succession, War of). The Prussian victory at Mollwitz (April 10, 1741) brought into the field against Austria all the powers which were ambitious of expansion at her expense: France, Bavaria, Spain, Saxony and Sardinia. Nor was the peril wholly external. Apart from the perennial discontents of Magyars and Slavs, the confusion and corruption of the administration, and the misery caused by the ruin of the finances, had made the Habsburg dynasty unpopular even in its German states, and in Vienna itself a large section of public opinion was loudly in favour of the claims of Charles of Bavaria. Yet the war, if it revealed the weakness of the Austrian monarchy, revealed also unexpected sources of strength.

Not the least of these was the character of Maria Theresa herself, who to the fascination of a young and beautiful woman added a very masculine resolution and judgment. In response to her personal appeal, and also to her wise and timely concessions, the Hungarians had rallied to her support, and for the first time in history awoke not only to a feeling of enthusiastic loyalty to a Habsburg monarch, but also to the realization that their true interests were bound up with those of Austria (see Hungary: History). Although, then, as the result of the war, Silesia was by the treaty of Dresden transferred from Austria to Prussia, while in Italy by the treaty of Aix-la-Chapelle in 1748 cessions were made at the expense of the house of Habsburg to the Spanish Don Philip and to Sardinia, the Austrian monarchy as a whole had displayed a vitality that had astonished the world, and was in some respects stronger than at the beginning of the struggle, notably in the great improvement in the army and in the possession of generals schooled by the experience of active service.

The period from 1747 to 1756, the year of the outbreak of the Seven Years' War, was occupied in preparations for carrying into effect the determination of Maria Theresa to recover the lost provinces. To give any chance of success, it was recognized that a twofold change of system was necessary: in internal and in external affairs. To strengthen the state internally a complete revolution of its administration was begun under the auspices of Count F. W. Haugwitz (1700-1765); the motley system which had survived from the middle ages was gradually replaced by an administrative machinery uniformly organized and centralized; and the army especially, hitherto patched together from the quotas raised and maintained by the various diets and provincial estates, was withdrawn from their interference. These reforms were practically confined to the central provinces of the monarchy; for in Hungary, as well as in the outlying territories of Lombardy and the Netherlands, it was recognized that the conservative temper of the peoples made any revolutionary change in the traditional system inadvisable.

Meanwhile, in foreign affairs, it had become clear that for Austrian-French alliance, and Seven Years' War. Austria the enemy to be dreaded was no longer France, but Prussia, and Kaunitz prepared the way for a diplomatic revolution, which took effect when, on the 1st of May 1756, Austria and France concluded the first treaty of Versailles. The long rivalry between Bourbons and Habsburgs was thus ended, and France and Austria remained in alliance or at peace until the outbreak of the French Revolution. So far as Austria was concerned, the Seven Years' War (q.v.) in which France and Austria were ranged against Prussia and Great Britain, was an attempt on the part of Maria Theresa to recover Silesia. It failed; and the peace of Hubertsburg, signed on the 15th of February 1763, left Germany divided between Austria and Prussia, whose rivalry for the hegemony was to last until the victory of Königgrätz (1866) definitely decided the issue in favour of the Hohenzollern monarchy.

The loss of Silesia led Austria to look for "compensation" Austria and Bavaria. elsewhere. The most obvious direction in which this could be sought was in Bavaria, ruled by the decadent house of Wittelsbach, the secular rival of the house of Habsburg in southern Germany. The question of the annexation of Bavaria by conquest or exchange had occupied the minds of Austrian statesmen throughout the century: it would not only have removed a perpetual menace to the peace of Austria, but would have given to the Habsburg monarchy an overwhelming strength in South Germany. The matter came to an issue in 1777, on the death of the elector Maximilian III. The heir was the elector palatine Charles Theodore, but Joseph II., who had been elected emperor in 1765, in succession to his father, and appointed co-regent with his mother - claimed the inheritance, and prepared to assert his claims by force. The result was the so-called War of Bavarian Succession. As a matter of fact, however, though the armies under Frederick and Joseph were face to face in the field, the affair was settled without actual fighting; Maria Theresa, fearing the chances of another struggle with Prussia, overruled her son at the last moment, and by the treaty of Teschen agreed to be content with the cession of the Quarter of the Inn (Innviertel) and some other districts.