From 1660 onwards, today (29th May) was celebrated in England as Restoration Day, Royal Oak Day or Oak Apple Day to commemorate the restoration of the Monarchy remembering how Charles escaped the Battle of Worcester by hiding in an Oak Tree.
Yet the public celebration of the Holiday was banned in 1859, but I can't find any information that points as to why Parliament chose to abolish it, merely that was the year when it ended. Any help on why this holiday was ended would be appreciated, thanks!
The holiday was less a civil holiday when established than a religious observance mandated by Parliament, which turned into a holiday. The religious observance was repealed in a package of similar repeals in 1859, removing them from the Book of Common Prayer. The why of this is that these observances (well, arguably not Oak Apple Day, but it was close enough to be a casualty of the repeal) were intended to reassert the power of the mainline Church of England and, through it, the state; they were repealed as conformity to CoE declined and it became politically untenable to maintain this form of power.
The English Civil War was, in part, a religious conflict. While there were many factors - political, social, and economic among them - the abolition (not banning) of Oak Apple Day is most closely tied to the religious aspects of the Restoration and changing attitudes towards religion in 1859 that made repealing the act politically attractive, or at least not unthinkable, to Parliament.
The Church of England was going through two major internal conflicts before and during the reign of Charles I. The first was over continued theological and liturgical reformation, and had two broad camps: those who felt that the English Reformation didn't go far enough in its break from Roman Catholicism, and those who felt that the Anglican Church was straying too far from its traditional roots. The second conflict was over church governance, and the factions here were more complicated.
Conflict in the Church of England Before the English Civil War
Reformation
Puritans generally supported:
Non-Puritans (sometimes "conformists" or "traditionalists;" not a great name for these) generally supported:
Church Governance
There was a very large faction that was for Presbyterianism but not otherwise reforming. They formed a fractious alliance with the Puritan faction to support the reform in governance, but were deeply uncomfortable with the more sweeping theological and liturgical reforms the Puritans were pushing. (There were also low church liturgy Presbyterians, but they didn't stick around too long).
The conformists, of course, formed the opposition to this as well.
It's important to point out that the Presbyterian/episcopalian divide was not contained within the Anglican Church (a little flippantly, I mean that it wasn't just theologians writing letters at each other about issues that nobody else had much stake in); its close ties to the state made it a contentious issue among monarchs and Parliament as well, and elections were often divided along these lines. The monarch, remember, is and was Supreme Head of the Anglican Church and not only derived legitimacy but wielded power through this position. Generally, parliamentarians trended towards presbyerianism while royalism was correlated with episcopalianism. These divisions were so deep that Charles I almost successfully divided the alliance against him by promising a Presbyterian Scottish army three years of presbyterian governance if they turned against their Parliamentarian allies that had ousted him.
Through all this was the persistent fear of and enmity to Catholicism and England's Catholic minority. The Puritans were able to politically weaponize this to much greater effect; Puritan reformers could, and did, call much of the traditionalists' beliefs "popery." People took these issues very seriously, but Presbyterianism was perhaps the biggest issue. It was not only a religious battle (though its adherents and opponents both sincerely believed in it/that it was heresy as articles of faith) but a political division over the power of England and its monarch as head of the Anglican Church, which Elizabeth had consolidated following the turmoil caused by Henry VIII's break from Catholocism, Edward VI's suppression of Catholicism, and Mary I's attempt to restore (or at least protect) Catholicism.
Charles I waded right into this battle, taking the side of the traditionalists. He supported high church Anglicism and was a strong episcopalian subscribed to his predecessors' (James I and Elizabeth I) beliefs that an attack on the authority of bishops was an attack on the authority of the king. His appointed Archbishop of Canterbury, William Laud, worked with Charles to enforce these beliefs; Laud eventually arrested and sentenced three outspoken presbyterians to maiming, which was considered an excessive punishment as these were gentlemen, a class generally exempt from corporal punishment. Attempts to enforce liturgical conformance and episcopacy in Scotland even lead to unrest in Scotland that erupted into the Bishops' Wars of 1639 and 1640. Accusations of Charles I's supposed sympathy for Catholics didn't help matters - he married a Catholic wife, thawed diplomatic relations with Catholic Spain, and failed dismally in a military intervention on behalf of French Huguenots.
Religious Divides and Reformation in the Interregnum
Parliamentarians won the English Civil War after years of bloodshed, eventually capturing and executing Charles I. The Long Parliament enacted Presbyterian reforms and replaced the Book of Common Prayer with the much looser Directory for Public Worship, which was less definitive on both practice and theology. The Rump Parliament (what remained after a partial military coup in 1648) further liberalized English religion with the repeal of the Act of Uniformity 1558, which ended mandatory worship at (and therefore conformity to the doctrine of) the established Anglican Church. Underground noncomformist sects, including Anabaptists, Quakers, and even Anglican Churches that were noncomforming to Anglican theology, openly emerged and started growing rapidly. Puritanism and Presbyterianism had won forever!
...except they didn't. Puritans in power rapidly expended the considerable political goodwill they had earned through ousting the unpopular Charles I, and the divisions among Puritan sects and between radical Puritans and more traditional Presbyterians deepened when they lost an opposition forcing them together.
Cromwell, an ardent and zealous Puritan, sought to enforce a strict morality over England and (despite his often-understated policies of tolerance to non-Anglican Protestant sects) stricter control over the spiritual purity of the Anglican Church. His moral reforms included the enforced ban of any work on the Sabbath (as far as fining people taking a long Sunday stroll), closing inns and theaters (through opera, bizarrely, was considered a spiritually elevating experience), swearing, immodest dress, and non-solemn celebration of Easter and Christmas. While it's still an open question over how strictly these were enforced - especially since Cromwell relied on decentralized military governors to oversee the enforcement of law and collection of taxes - it should go without saying that these laws were deeply unpopular among the general population, especially as the military governors relied on local militias of zealous religious enforcers. He also appointed commissioners to judge whether the leaders of parishes and schools were acceptable for office. Cromwell was also remarkably tolerant of Jews - both for secular reasons (wishing to emulate the strong Dutch economy's reliance on Jewish lenders) and religious reasons (believing that they were instrumental in the returning of the Messiah), and advocating for welcoming Jews into England and (peacefully) converting them. This was also a wildly unpopular policy. All this combined eroded support for reforming politics.
Traditionalist Presbyterians were deeply unhappy with the Rump Parliament's and especially with Cromwell's policy. They didn't want this much religious liberalizing or Puritan reforms, so when the Protectorate collapsed under Oliver Cromwell's less-capable son and the dust of the ensuing leadership crisis settled, Parliament was recalled and held elections that were intended to ensure a Presbyterian and Parliamentarian majority. Puritans, having long since fractured politically and theologically (and their popular support squandered by the Cromwell regime) had little sway in formal politics at this point. However, the legislative election requirements were not strictly enforced and a moderate Parliament was installed, which responded to Charles II's overtures of toleration and mercy to Interregnum leaders in exchange for his restoration to the monarchy. Oak Apple Day was established in the Book of Common Prayer as a day of thanksgiving for the Restoration and end to the conflict.