The Calendar (11 page)

Augustine, however, was hardly the last word on how to treat the past and future, and time itself. Indeed, his mysticism and reliance on faith would continue to bump up against those who wanted to categorize and measure the past--especially the Christian past--and those who wanted to plan or to predict the future in a systematic and scientific manner. It was the tension between these two ideals, the sacred and the profane, that would dominate the next millennium in Europe, though one side was clearly the victor--even as Rome’s political and cultural collapse combined with Augustine’s philosophy of anti time to all but extinguish any scientific interest in the calendar, or in making it more accurate.

And yet, as we shall see, the light of scientific curiosity was never quenched entirely. Even in the darkest days after the fall of Rome a progression of isolated monks and thinkers remained inquisitive, inasmuch as they were able, about nature and science--including ways to better measure what Augustine said was unmeasurable: time.

Augustine himself conceded that time reckoning could be tolerated in one area where the sacred and the profane could not be disentangled: calculating and predicting the date for Easter. This could be determined only by someone knowledgeable in astronomy and mathematics--and so the calculation of the date of Easter became the slender thread that science would hang by over the coming centuries. This was ironic, given that Christians who condemned science as a blasphemous intrusion into God’s domain were forced to rely on science to date the most mystical event in their pantheon of miracles and otherworldly epiphanies: the resurrection of Christ.

The history of science in the Middle Ages would have been very different if the bishops at Nicaea had decided simply to name a fixed date for Easter in the solar calendar. But they did not. Instead, in the wake of Nicaea, Christians developed what became a complex equation to determine the proper day, forcing time reckoners to return to something Caesar had dispensed with centuries earlier: a dependence on the moon. Almost by accident they found themselves confronting the ancient conundrum of trying to correlate the phases of the moon with the orbit of the earth--the same problem that had plagued calendar-makers from China and Babylon to pre-imperial Rome as they tried to fuse a 354-day lunar year with a roughly 365 1/4-day solar year.

Even today this lunar-solar link-up is a challenging astronomical problem, one that must compensate for a complicated range of gravitational tugs and pulls from the sun, moon and other celestial bodies; the slow degradation of the orbits of the earth and moon over time; the slightly elliptical orbits of the earth and moon; and the spin of the earth on its axis--all factors that Christian time reckoners in the era of Nicaea had no inkling about when they devised their basic formula for Easter. Below is a 14-step algorithm devised by modern-day Catholic astronomers, who factor in some of the variables to come up with an almost precise Easter date--
almost,
because there are always minute fluctuations in the movements of the earth, moon, planets and stars that make an absolutely exact measurement impossible to predict.

a                                 =      year% 19
b                                 =      year/100
c                                 =      year%100
d                                 =      b/4
e
                                
=
     
b% 4
f
                                 =      (b+ 8)/25
g                                 =      (b-
f
+ 1)/3
h
                                 =      (19 * a + b - d - g + 15)%30
i                                  -       c/4
k                                 =      c%4
l
                                  =      (32 + 2*e + 2*
i
--h--k)%7
m                               =      (a + 11 * h + 22 *
l
)/451
Easter month          =      (
h
+ 1 - 7 * m + 114)/31 [3 = March, 4 = April]

p                                 =      (
h
+ 1 -7 * »i + 114)%31
Easter date              =     
p
+ 1 (date in Easter month)

/                         =      division neglecting the remainder
%                       =      division keeping
only
the remainder
*                        =      multiply

As far as anyone knows, the bishops at Nicaea did not officially assign anyone or anyplace to make the official Easter determination, though the task naturally fell to Alexandrian astronomers: Even before the great council, the bishops of Alexandria had dispatched letters to other churches announcing the date when they would celebrate the Easter feast. Few details are available about these early calculations, though the Alexandrians before and after Nicaea apparently used the old 19-year cycle of lunar months--the Metonic cycle--to link the moon to the solar year.

The Alexandrians also seem to have been the ones who fixed the date for the spring equinox on 21 March, a change from Caesar’s day, when the equinox was set on 25 March. This shift may have been an attempt to compensate for the drift in Caesar’s calendar against the true solar year, though the true drift between Caesar’s reform in 45 BC and the Council of Nicaea in AD 325 was closer to three days than to four.

At least two astronomers are known to have created time charts predicting future dates for Easter. Both were also bishops of Alexandria--Theophilus (bishop 385-412), whose tables covered a 100-year span between 380 and 480, and his nephew Cyrillus, who succeeded his uncle and devised a 95-year table covering the Easters between 437 and 531. Both charts were reasonably accurate, though they suffered from a small flaw in the Metonic cycle--the fact that 235 synodic lunar months do not fit exactly into 19 Julian years, falling one day long. Over the course of 95 years (five 19-year cycles) this excess of a single day amounts to a five-day mistake in matching up the phases of the moon with the Julian calendar--a problem early time reckoners attempted to deal with by intercalating a day into each 19-year cycle.

A more serious problem for Easter reckoners after Nicaea was political rather than scientific. Not every city went along with the Alexandrians’ methods for dating Easter, despite the council’s dictate that the Easter question should be addressed uniformly for all Christians.

The most pronounced difference was between the churches of the East, which followed Alexandria’s lead, and the churches of the West, which looked to Rome--a split that went far beyond issues of Easter and the calendar as the Roman world slowly divided itself along a fault line of East and West, Greek and Latin, Hellenistic and Roman. The Easter differences between Rome and Alexandria were small but important, particularly because they foreshadowed the eventual split between the Greek and Latin churches, which to this day celebrate Easter on different dates.

The first East-West Easter squabble concerned dating the equinox. The Egyptians continued to use 21 March. Rome, however, used Caesar’s original date: 25 March. The other problem involved methods for matching up the solar year and the phases of the moon. Romans used a system developed in the mid-third century based on an 84-year cycle of lunar months divided into years, which was accurate within a day and a half. This differed from the Alexandrians’ 19-year cycle, which was both more precise and easier to keep properly adjusted.

In most years the result of these subtle differences meant nothing, since both methods came up with the same day for Easter. A few years, however, were wildly off. For example, in 387 Augustine noted angrily in a letter that the Alexandrians were celebrating Easter on 25 April and the Romans on 18 April. Worse still, he fumed that the Arian churches of Gaul--still thriving despite Nicaea’s condemnation of their founder’s doctrine--had come up with a
third
date. Using yet another formula, they celebrated Easter that year on 21 March.

Dissension over details in the Easter calculation was one reason why Augustine at times became impatient with mathematicians and others who seemed obsessed with numbers and with measuring time. The bishop of Hippo had little patience with such worldly minutiae as he went about completing the process set in motion by Constantine and the bishops at Nicaea to subjugate time to God, and by extension to the Church. Christians had long been thinking this way, but not until Augustine did anyone lay it all out and elevate the issue of God’s time from the simple language and logic of the apostles to the high scholarly realm of philosophy in the ancient tradition, an intellectual legitimatization that the church had lacked before.

As the hordes of
barbari
swarmed across Gaul and Iberia in the years after the Mainz invasion of 406, tribes fanned out to plunder in every direction. One band of Vandals marched all the way from their homeland in modern Hungary to cross the Strait of Gibraltar in 429, when they began terrorizing the provinces of Mauretania and Numidia, finally reaching Augustine’s city of Hippo in 430.

The ageing bishop, then 75 years old, joined in the collective effort to organize the city’s defences and to care for the thousands of refugees from other Roman towns pressed inside the city walls. By mid-summer Hippo was completely surrounded by the
barbari,
who set up a fourteen-month siege. Inside the walls the people grew hungry as the Vandals hemmed them in from land and sea. They then became sick with an illness that spread quickly through the crowds living in makeshift, unsanitary conditions. Stricken with fever, Augustine himself was sent to bed sometime in August. He died a short time later, several months before the invaders conquered the city, which Rome was forced to cede to the Vandals along with Carthage eight years later in a desperate gambit to appease these
barbari
before they captured other key African provinces supplying grain to Italy.

The Vandals, revelling in their plunder as they moved into the shattered cities of Roman Africa, formed a poignant backdrop to Augustine’s death. For as he died the ancient world of Caesar, Augustus and Constantine was also dying, as was time as it had been understood in ancient times.

But time did not entirely stop--not yet, anyway--despite the empire’s final demise in 476 with the assassination of its last emperor, Romulus Augustulus, 46 years after Augustine’s death. For even as Rome’s invaders fought over their spoils, a brief and improbable window opened up in Italy late in the fifth century: a moment of peace and political stability that allowed three remarkable scholars living in Rome to flourish in what was truly the last gasp of the ancient world. Each in his own way affected time, the calendar and how people would perceive them in the dark ages fast approaching. Two of them were sons of ancient patrician families in Rome, young intellectuals who experienced meteoric careers as scholars and political appointees. The other was a Scythian monk and theologian about whom little is known.

By the time these three young men were living in Rome, at roughly the turn of the sixth century, the city had again changed hands. Just a few years earlier the German general Odoacer, who deposed Romulus Augustulus, was himself ousted and killed by the Ostrogoths in 493. Meanwhile Gaul had cracked into shifting territories fought over by German warlords leading bands of Burgundians, Franks, Alemanni, Alemanes, Goths and Suessiones. In Britain bands of Picts, Angles and Saxons fought each other as a few surviving enclaves of Romano-Britons grimly hung on, pushed west into modern-day Wales. To the south the Visigoths seized all but the far west of Iberia; in North Africa the Berbers and Vandals controlled the entire coast and the waters of the western Mediterranean with a fleet built by the Vandal king Gaiseric in Carthage. In the East the old empire persevered, but barely, getting some breathing space early in the sixth century when invading Persians, who had nearly crushed them, had to break off their conquest to beat back the Huns ravaging their own northern and eastern frontiers.

Rome itself was a shattered city, sacked repeatedly over the previous century. By now the great buildings, homes and monuments were mostly stripped of precious metals. Basilicas, massive baths and the labyrinth of palaces on Palatine Hill were still in use but decaying as a depleted civil service struggled to maintain what they could. Statues lay smashed on empty streets, and entire neighbourhoods fell into ruin as most people abandoned the city. Markets lacked the grain and produce supplied for centuries from colonies now lost. Romans facing one blow after another had begun a centuries-long process of peeling off the marble facades and dismantling the stone from one building after another to use in new construction or to build defences. Only those basilicas and temples taken over by the Church remained more or less untouched, though most prelates bore little regard for the art and architecture of pagans. One can still see divots on columns outside temples converted to churches, gouged by Christians who wrapped chains around them and tried to pull down these old ‘pagan’ structures, but could not because they were built too well.

Disastrous decline seemed inevitable in Italy, as it did elsewhere in the former empire, until the arrival of an unexpected saviour in the guise of King Theodoric, whose powerful Ostrogothic army had swept in from the east to take over Italy and parts of what are now France, Austria and the Balkans. An unusually enlightened leader and clever military strategist, Theodoric ruled Italy for 33 years, providing stability for the first time in a century with a combination of a powerful army and restoration of the old imperial civil structure. A great admirer of Roman culture, Theodoric, ruling from Ravenna, capital of the last few emperors in the West, set about repairing and rejuvenating what he could of Italy’s battered cities. In Rome he rebuilt palaces, shored up roads and reopened aqueducts destroyed by the
barbari.
It was during this brief and all too furtive flash of Roman renaissance that our three young men were able to pursue political careers and intellectual pursuits, including work on time and the calendar, almost as if the old empire had not died.