When William Byrd died on July 4, 1623, the Cheque Book of the Chapel Royal noted the passing of “a Father of Musick.” That’s not an exaggeration: Today, his legacy as a composer flexible in style and firm in belief still resounds across England and the world of choral music.

As a composer Byrd was, in essence, a miniaturist, said Peter Phillips, the founder of the early music ensemble the Tallis Scholars — “a kind of jigsaw composer” who wrote “little snippets of music that fitted together mind-bogglingly well.” Phillips compared Byrd to the painter Paul Klee, a thinker for whom “the little things matter very much.”

That small-scale thinking could be easily built up into larger textures, such as in “Ad Dominum cum tribularer” or the “Great Service”; boiled down to its essence, in the concise works of his “Gradualia” collections; and applied to a variety of different genres. Outside the church, Byrd wrote florid music for the virginal, and pioneered the consort song, a precursor to the lute song.

Yet as a man, Byrd is known as being far less accommodating.

Confident and ambitious in his early years, and obstinate and increasingly litigious later on, Byrd “certainly doesn’t emerge as a very benevolent figure from the records we have of his dealings,” said Andrew Johnstone, an assistant professor of music at Trinity College, Dublin. But Byrd’s stubbornness — bordering on irascibility — came in the face of religious and professional opposition.

William Weston, a contemporary who was a Jesuit, described Byrd as someone who “had sacrificed everything for the faith.” Because Byrd held onto a firm — though not necessarily static — belief in Catholicism, his life and music were consequently shaped by the increasingly hostile climate toward the Catholic population that remained in England during the Elizabethan period that followed Henry VIII’s break from the Roman Catholic Church a generation before.

Celebrations like this 400th anniversary of Byrd’s death come with a “baked-in sadness,” said Patrick Dunachie, a member of the King’s Singers, because “for lots of composers in this era, you can only really celebrate their death, because nine times out 10, it’s impossible to know quite when these people were born.”

Byrd was born around 1540, into a family of self-described “gentlemen.” Otherwise, details about his early years are murky until he began his long relationship with the Chapel Royal as a child, and maybe even as a chorister.

It was not a conventional chapel, Johnstone noted, but a semiautonomous corporation of musicians in service of the monarch. The Chapel Royal also brought Byrd into contact with its then-organist, Thomas Tallis, who became his teacher and mentor and later a collaborator.

After studying with Tallis, in 1563, Byrd left to take up the post of organist and master of the choristers at Lincoln Cathedral. The city of Lincoln “would have been a happy, healthy place to be a Catholic at the time,” Johnstone said, given the population’s relatively high concentration of Catholics. But the cathedral’s governing chapter disapproved of Byrd’s organ playing and suspended his salary was suspended in 1569.

“The complaint,” Phillips said, “was that he would play much too much when it wasn’t wanted, and he wouldn’t play at all when it was wanted.” Others have pointed to Byrd’s protracted organ playing, which was described as “popish.”

In 1572, Byrd returned as a Gentleman of the Chapel Royal (an adult male singer), earning a generous stipend that was his main source of income until his death.

Byrd was, for the majority of his working life, a Catholic living under the Protestant rule of Queen Elizabeth I, but the situation was more fluid and complicated than that. Unlike his Catholic contemporaries John Dowland, John Bull and Richard Dering, Byrd didn’t flee the country, opting instead to stay and, in part, abide by the new, state-enforced Protestantism. And support for Byrd’s burgeoning career came from both England’s extant Catholic establishment and the queen herself.

The quote “I have no desire to make windows into men’s souls” is regularly attributed to Elizabeth, during the early moments of her reign. “It was clear,” Johnstone said, “that she was making it possible for the Catholics among her subjects to continue to have this indemnity of conscience when it came to the essential religious matter of making your Communion,” the primary difference between the two religions at the time.

But in the case of Byrd, Elizabeth went further than simply looking the other way. As punishments for recusancy — the statutory offense of missing church, which subsequently targeted Catholics — increased, and as fines were put in place for travel outside an assigned parish, Byrd “was given carte blanche by the court to travel around as much as he needed to,” Johnstone said. And in 1592, a prosecution of Byrd was stopped by direct order of the queen.

Elizabeth also played a significant part in Byrd’s financial affairs, granting him and Tallis the first monopoly on printed music in England, in 1575. The pair’s first collection — “Cantiones quae ab argumento sacrae vocantur,” roughly translated as “Songs that are called sacred on account of their texts” — featured a large mixture of musical material but was ultimately a financial disaster, requiring Byrd and Tallis to petition the queen for more money. (When Tallis died 10 years later, Byrd wrote an elegy for solo voice and viols, “Ye Sacred Muses,” which concludes with the famous line: “Tallis is dead, and Music dies.” Ironically, Tallis’s death produced a flurry of published music from Byrd, realizing then that he had a potentially lucrative publishing monopoly all to himself.)

Having returned to London in 1577, Byrd eventually moved out into Middlesex, close to a manor of his first Catholic patron, Lord Thomas Paget, amid a period of troubles for Catholics. The killing of Jesuits, such as Edmund Campion in 1581, signaled a new wave of hostility toward Catholics in England.

Byrd responded to Campion’s death musically, both in his setting of the Jesuit Henry Walpole’s “Why do I use my paper, ink, and pen?” and in the highly symbolic “Deus venerunt gentes.” Through allegorical biblical passages, particularly around Jerusalem’s destruction and the suffering of the Israelites (such as “Ne irascaris Domine”), Byrd would continue to comment metaphorically on the state of Catholicism in England.

When Byrd eventually moved out to rural Essex, in the mid 1590s, he could rely on further support from the Catholic establishment in Britain. From the more private surroundings of Stondon Massey, where Byrd also developed interests both in property and pursuing legal disputes with tenants, Byrd began to construct distinctly liturgical Catholic music, including the now-popular Masses for Three, Four and Five Voices, and two sets of “Gradualia” covering the whole Catholic calendar, for private performances at Ingatestone Hall, which was owned by Sir John Petre, a recusant and, later, a dedicatee of Byrd.

For comparison, the “Gradualia” collections were “similar to what J.S. Bach was doing in setting specific cantatas for specific Sundays,” said Will Dawes, the conductor of the Byrd-A-Thon, a complete performance of Byrd’s Latin church music that took place in Oxford in February.

Byrd’s music from that time is “wonderfully intimate,” Dawes said. “Four singers can sing it one-to-a-part, and it can feel so much more powerful than a Mahler symphony.” Written at a time when masses were clandestine observances taken in residences, under constant threat from the authorities, “it must have made the feelings involved so much more powerful,” he added.

But there is also levity in Byrd’s domestic music. Pieces like the charmingly rustic song “Who Made Thee Hob?” show, Dunachie said, that “it doesn’t take a whole lot of digging to find a whole different sound world.”

Carried through all Byrd’s vocal music is economy, lucidity and emotional clarity in his approach to text — at a time when words and their representations were contested so painfully. He, Dawes said, “fits in the same category as Benjamin Britten and Henry Purcell as one of the best setters of text from any composer in England.”