Frederick has strengthened his position in Southern…

The fabric of Saint Peter’s Basilica has fallen into such bad repair by 1420, when the papacy is reestablished in Rome, that plans are drawn up to extend and strengthen all parts of the basilica.

Pope Martin V engineers the restoration of the papal authority both at Rome and within the Papal States, where the pontiff is nearly an absolute monarch, and on whose financial resources the papacy is increasingly dependent.

Martin is less successful in his attempts to suppress the Hussites in Bohemia and to effect reunion with the Greek church.

A firm defender of papal prerogatives, he nevertheless abides by the restrictions that the Council of Constance had already imposed on them.

In accordance with the council's decree Frequens, he convokes the general councils of Pavia-Siena in 1423 and Basel in 1431.

He dies on February 20, 1431; his successor takes the name Eugene IV.

Genoa-born Leon Battista Alberti, receives his humanistic training at the University of Padua and studies law at Bologna.

In 1428, at twenty-four, he is an aide of the papal legates to Burgundy and Germany.

In that year, he begins writing, in Latin and Italian, various works of prose and poetry.

In 1431, Alberti becomes papal secretary in Rome, where he begins the study of ancient monuments.

Paolo Uccello, commissioned in 1436 to paint a posthumous equestrian monument of the famous English mercenary soldier Sir John Hawkwood for Florence Cathedral, creates an extraordinary fresco portraying a monumental stone statue; the pedestal is seen from below, but the horse and rider are seen from the side.

Florence’s Gothic cathedral of Santa Maria del Fiore is consecrated in 1436.

The ideal church type of the age is based on the centralized plan, admired by architects and theoreticians for its geometrical purity and clarity (and thus to heavenly order), and directly exemplified by Florentine sculptor-architect Filippo Brunelleschi's remarkable 1434 design for the first centrally planned church of the Renaissance, Florence’s vast (and still unfinished) Santa Maria degli Angeli (also called the Duomo of Florence): a domed octagon with eight radiating chapels.

His centralized plan, formed by a ring of eight piers, becomes the ideal among his Florentine contemporaries and his followers in Rome.

In 1436, he begins the church of Santo Spirito, using such traditional Italian Romanesque elements as a basilican plan, round arches, and a flat ceiling, but combines these with a new sense of proportion, the use of Corinthian columns, and a dome over the crossing of nave and transepts.

Italian polymath Leone Battista Alberti had moved in 1434 to Florence, becoming a member of the inner circle of humanists in Tuscany, among them the sculptor Donatello, and has gained recognition as an authority on art and classical literature.

He has become especially interested in the work of Brunelleschi, to whom he dedicates the Italian edition of Della pittura (On Painting), a treatise on the theory and technique of painting published in 1436, in which the author sets forth all that is currently known on the subject.

(Alberti had dedicated the 1435 Latin edition to Gian Francesco Gonzaga of Milan.)

Cosimo de Medici grants the Jews of Florence the first formal charter for money lending activities in 1437.

The wealthy Humanist Niccolò Niccoli is one of the chief figures in the company of learned men who have gathered around Cosimo de' Medici, and his intellectual quarrels with other noted Humanists have created a sensation in the learned world.

His collections of ancient art objects and library of manuscripts of classical works have helped to shape a taste for the antique.

He has copied and collated ancient manuscripts, correcting the texts, introducing divisions into chapters, and making tables of contents.

Many of the most valuable manuscripts in the Laurentian Library in Florence are by his hand, among them those of Lucretius and of twelve comedies of Plautus.

Niccoli's private library is the largest and best in Florence, and he also possesses a small but significant collection of ancient works of art, coins and medals.

He is also an accomplished calligrapher whose slightly inclined antica corsiva script has influenced the development of italic type.

He dies on February 3 of this year.

Donatello continues to explore the possibilities of the new shallow carving technique known as schiacciato (“flattened out”) in his marble reliefs of the 1420s and early 1430s.

The most highly developed of these are “The Ascension, with Christ Giving the Keys to St. Peter,” which is so delicately carved that its full beauty can be seen only in a strongly raking light; and the “Feast of Herod” (1433–35), with its perspective background.

The large stucco roundels with scenes from the life of St. John the Evangelist (about 1434–37), below the dome of the old sacristy of San Lorenzo, show the same technique but with color added for better legibility at a distance.

Lorenzo Ghiberti has by this time cast the reliefs for the second pair of doors for the Florence Baptistery.

(The work so closely complements Alberti's theories in his pioneering 1435 “Treatise on Painting,” that scholars have proposed him as Ghiberti's inspiration.)

Alberti in this year creates the earliest known peep shows: the perspective views said to have been painted in transparent colors on glass and lighted from behind for various effects, from sunshine to moonlight.

Florentine painter Fra Filippo Lippi, also called Lippo Lippi, an orphan who was raised in a Carmelite monastery, had become a monk at the age of fifteen, but, finding religious life unsuitable, had left the Carmelite order in about 1431 at the age of twenty-five, later marrying Lucrezia Buti.

Like the late Masaccio (who may have been his teacher)—Lippi achieves a sense of grandeur in his earliest datable work, a “Madonna Enthroned” painted in 1437, by using monumental figures, heavy draperies, and lighting designed to heighten the sculptural effect.

The detailed domestic scenery in the background implies the influence of the Flemish masters; he may also have looked to the relief sculptures of Donatello and Ghiberti for inspiration.

Lippi's synthesis of these influences enables him to bring new ideas to painting.

Plague forces the council at Ferrara to move to Florence on January 10, 1439, and is thus known as the Council of Ferrara-Florence.

Here, the Council affirms the so-called Peterine theory, according to which Jesus Christ conferred the position of primacy in the church upon Peter alone, thus grounding his successors' claim to jurisdictional primacy in the church.

After protracted and difficult discussion of their theological differences, the Greeks agree to accept the Filioque and also the Latin statements on purgatory, the Eucharist, and papal primacy.

Isidore of Kiev has attended the council, first in Ferrara, then in Florence, at which he is one of six Greek spokesmen.

Together with the Greek cardinal John Bessarion, he draws up the document of unification, Laetentur Caeli, under which the two churches are formally reunited on July 6, 1439, Constantinople agreeing to submit to the authority of Rome.

The Orthodox leaders will have trouble, however, winning approval from the clergy at home.

The council also negotiates reunion with several smaller eastern churches, such as the Armenian church, Nestorian church, Jacobite church, and Eastern Rite churches, and challenges the conciliar theory enunciated at the councils of Constance and Basel.

Cosimo de' Medici and Pope Eugene IV had requisitioned the decaying convent of San Marco in 1436 and invited the Dominicans to build and decorate a new monastery.

In collaboration with the architect Michelozzo, Fra Angelico and his assistants have frescoed numerous scenes from the life of Christ in the forty-four monks' dormitory cells and connecting corridors.

Angelico has designed each of these clearly drawn frescoes, such as the San Marco “Annunciation,” to enhance the contemplative, religious setting.

In the (now overcleaned) altarpiece for San Marco, painted by Angelico in 1438-39 and entitled “Madonna and Saints in a Sacred Conversation” (he has created the form called “Sacra Conversazione”), the artist employs natural light and Alberti's systematic perspective to produce a remarkable rendering of the human figure.

The versatile Alberti, better known as an architect, publishes a lengthy treatise, “On the Family,” written from 1433 to 1439; its wisdom and rationality mirror the abiding concern of Italian letters with social and ethical topics.

Franco-Flemish composer Guillaume Dufay, highly respected not only for his music but also for his learning, has attained influential appointments in the church, taking part in the Council of Basel as a delegate from Cambrai.

He had remained a member of the papal choir in Rome until 1434 when, because of a crisis in the finances of the papal choir, and to escape the turbulence and uncertainty during the struggle between the papacy and the Council of Basel, he had entered the service of Duke Amadeus VIII of Savoy for a year.

In 1435 he was again in the service of the papal chapel, but this time it was in Florence.

In 1436, Dufay had composed the festive motet Nuper rosarum flores, one of his most famous compositions, which is sung at the dedication of Brunelleschi's dome of the cathedral in Florence, where Eugenius lives in exile.

During this period Dufay also begins his long association with the d'Este family in Ferrara, some of the most important musical patrons of the Renaissance, and with which he probably had become acquainted during the days of his association with the Malatesta family; Rimini and Ferrara are not only geographically close, but the two families are related by marriage, and Dufay composes at least one ballade for Niccolò III, Marquis of Ferrara.

In 1437, Dufay had visited the town.

The struggle between the papacy and the rump Council of Basel has continued: when the rump council had suspended Eugenius, he had excommunicated its members.

The council, with only seven bishops present, had declared Eugenius deposed and in 1439 elects as his successor a layman, Duke Amadeus himself, who takes the name Pope Felix V.

Leonello gives Ferrara considerable distinction in the fields of art and culture as the city comes to represent a lively center of culture and humanism, filled with painters (Pisanello, Bellini, van der Weyden, Mantegna), architects (Alberti), and scholars (centering on Guarino Veronese).

Jacopo Bellini, born in Venice, had been a pupil of Gentile da Fabriano.

In 1411–1412, he was in Foligno, where with Gentile he had worked at the Palazzo Trinci frescoes.

In 1423, Bellini was in Florence, where he knew the new works by Brunelleschi, Donatello, Masolino da Panicale and Masaccio.

In 1424, he had opened a workshop in Venice, which he is to run until his death in 1470.

Many of his greatest works, including the enormous Crucifixion in the cathedral of Verona (1436), have disappeared.

From about 1430 is the panel with Madonna and Child, in the Accademia Carrara, once attributed to Gentile da Fabriano.

In 1441, at Ferrara, where he was at the service of Leonello d'Este together with Leon Battista Alberti, he executed a portrait of that Marquess, now lost.

To this period belongs the Madonna dell'Umiltà (Virgin of Humility, adored by a prince of the House of Este, 1440), probably commissioned by one of the brothers of Leonello.

Alberti, between 1428 and 1443, has written, in Latin and Italian, love poems and dialogues, a Latin comedy, fables, and treatises on agriculture, the care of horses, law, marriage, sculpture, and virtue.

Della tranquilita dell' animo (“On Peace of Mind”) written in 1442, is among the finest of these.

Nineteen-year-old painter Andrea del Castagno has won recognition in Florence for a representation, on the facade of the Palazzo del Podesta, of hanged men who had been traitors to Florence during the Battle of Anghiari in 1440.

This work earns him the sobriquet “Andreino degli Impicatti" ( "Little Andrew of the Hanged Men" ).

Upon his return from Venice in 1443, Castagno works at the Duomo, where he supplies the cartoon for the stained-glass window depicting the deposition of Christ. (Although little is known of Castagno's earliest training, his figure drawing, characterized by a monumental, sculptural grandeur even in his earliest works, indicates that he is strongly affected by the works of Masaccio. Domenico Veneziano, Donatello, Ghiberti, and Piero della Francesca are also influential in his development.)

Florentine sculptor and architect Michelozzo di Bartolommeo, like Brunelleschi, has received many commissions from Cosimo de' Medici, including those for the library of the Convent of San Marco, constructed between 1436 and 1443.

Bernardo Rossellino, a noted Florentine architect who had worked on the Duomo from 1441-44, works with Leon Battista Alberti on the Palazzo Rucellai in Florence from 1446 to 1451.

Bernardo’s sculpture reveals a clarity of form visible in his major work, the tomb of Leonardo Bruni in Santa Croce, Florence, executed in 1444-47, for which he employs a triumphal arch to create a new type of sepulchral monument.

Sigismondo Pandolfo was born in Brescia, northern Italy, the elder of the two illegitimate sons of Pandolfo III Malatesta and Antonia da Barignani.

His younger brother, Malatesta Novello, was born in Brescia on August 5, 1418.

An elder (and also illegitimate) half-brother, Galeotto Roberto Malatesta, born in 1411, was the issue of the relationship of their father Pandolfo III with Allegra de' Mori.

Following the family's tradition, Sigismondo, after the death of his father, had debuted as man-at-arms at the age of thirteen against his relative Carlo II Malatesta, lord of Pesaro and Pope Martin V's ally, who aimed to annex Rimini, Cesena and Fano to his territories.

After his victory, Sigismondo had obtained, together with his brothers Galeotto Roberto and Domenico, the title of Papal vicar for those cities.

In 1431, albeit with inferior forces, he had repelled another invasion by the Malatestas of Pesaro.

When, soon afterwards, his elder brother abdicated, he became lord of Rimini, at the age of fifteen.

In 1432, he had accepted the command of a papal corps, defeating the Spanish condottiero Sante Cirillo and thwarting Antonio I Ordelaffi's attempt to capture Forlì (1435–36).

However, the following year Sigismondo occupied the papal city of Cervia and was excommunicated; he was soon pardoned and created commander of the papal army.

Later, he fought in Romagna and the Marche alongside Francesco Sforza.

In the meantime he married his niece Ginevra d'Este, Niccolò III's legitimate daughter by his second wife Parisina Malatesta, first cousin of Sigismondo.

On October 12, 1440, she died, and rumors spread that she had been poisoned by Sigismondo.

Two years later, he married Polissena Sforza, Francesco I's illegitimate daughter; they had two children: a son, Galeotto, born in 1442 and who only lived a few months, and a daughter, Giovanna, born in 1444 and later Duchess of Camerino by marriage.

In this period, he had fought several times against the condottiero Niccolò Piccinino: first, in 1437, as a Venetian commander, he was defeated at Calcinara sull'Oglio.

Later, while defending his lands from the papal invasion army led by Piccinino, Federico III da Montefeltro and Malatesta Novello, he had crushed them at Monteluro, managing to obtain some territories of Pesaro, although the latter was successfully defeated by Federico's forces.

In his restlessness, he had betrayed Sforza twice, but he also betrayed his momentary ally against him, Niccolò Piccinino.

Enmity against Sforza had turned into true hatred when his father-in-law bought the signory of Pesaro from Carlo Malatesta.

Therefore, Sigismondo had allied with Pope Eugene IV and the Sforza duke of Milan.

Later, he was hired by King Alfonso V of Naples, but soon afterwards received money for a condotta to be spent in the service of Florence against Alfonso.

In 1445, he had forced the Neapolitans to raise the siege of Piombino in Tuscany.

His second wife Polissena had died under mysterious circumstances in 1449.

Francesco Sforza claims that Sigismondo had had her drowned by one of his servants, but this has remained unconfirmed.

During his two marriages, he has had numerous mistresses, but only two are well known: Vannetta dei Toschi, who bore him a son, Roberto, in 1441, and Isotta degli Atti, who bore him four children: Giovanni (who died in infancy), Margherita (later wife of Carlo di Fortebraccio), Sallustio and Antonia (also called Anna), later the first wife of Rodolfo Gonzaga, Lord of Castiglione delle Stiviere, who will behead her in 1483 when she is discovered in adultery.

Sigismondo commissions Leon Battista Alberti to redesign the exterior of the church of San Francesco in Rimini as a shrine to the Malatesta court members and family.

Now known as the Tempio Malatestiano (Malatesta Temple), it bears the date 1450.

Alberti’s original architectural designs include the Palazzo Rucellai in Florence, constructed in 1446-51 and executed, at least in part, by Bernardo Rossellino.

Its facade is one of the first to proclaim the new ideas of Renaissance architecture based on the use of pilasters and entablatures in proportional relationship to each other.