Problem: Background: The Nitty Gritty Dirt Band, an American country rock band, has existed in various forms since its founding in Long Beach, California in 1966. The group's membership has had at least a dozen changes over the years, including a period from 1976 to 1981 when the band performed and recorded as the Dirt Band. Constant members since the early times are singer-guitarist Jeff Hanna and drummer Jimmie Fadden. Multi-instrumentalist John McEuen was with the band from 1966 to 1986 and returned during 2001 departing once again in November 2017.
Context: The group was inactive for a 6-month period after Paint Your Wagon, then reformed with Jimmy Ibbotson replacing Chris Darrow. With William McEuen as producer and a renegotiated contract that gave the band more artistic freedom, the band recorded and released Uncle Charlie & His Dog Teddy, issued in 1970. Embracing a straight, traditional country and bluegrass sound, the album included the group's best-known singles; a cover version of Jerry Jeff Walker's "Mr. Bojangles", Michael Nesmith's "Some of Shelley's Blues", and four Kenny Loggins songs including "House at Pooh Corner", the first recordings of Loggins's songs. Their version of "Mr. Bojangles" became the group's first hit, peaking at #9 on Billboard's all genre Hot 100 chart, with an unusual 36 weeks on the charts. The next album, All The Good Times, released during early 1972, had a similar style. Nitty Gritty Dirt Band next sought to solidify its reputation as a country band when band member John McEuen asked Earl Scruggs if he would record with the group. Earl's "yes" was followed the next week when John asked Doc Watson the same question, receiving the same answer of 'yes'. This set in motion the further addition of other artists, and with the help of Earl and Louise Scruggs, they set to traveling to Nashville, Tennessee and recording what was to become a triple album, Will the Circle Be Unbroken with Nashville stalwarts Roy Acuff, Earl Scruggs, and Jimmy Martin, country pioneer Mother Maybelle Carter, folk-blues guitarist Doc Watson, Merle Travis, Norman Blake, and others. The title is from the song, "Will the Circle Be Unbroken (By and By)", as adapted by A. P. Carter, and reflects the album's theme of trying to tie together three generations of musicians: long-haired boys from California and older veterans of the middle American establishment. The track "I Saw the Light" with Acuff singing, was a success, and the album received two nominations for Grammy Award. Veteran fiddler Vassar Clements was introduced to a wider audience by the album and gave him a new career. The band also toured Japan twice soon after this period. After the next album Les Thompson left the group, making the band a foursome. Stars & Stripes Forever was a live album that mixed old successes such as "Buy for Me the Rain" and "Mr. Bojangles" with Circle collaborations (fiddler Vassar Clements was a guest performer) and long storytelling spoken-word monologues. A studio album, Dream, was also released. During July 1974, the band was among the headline acts at the Ozark Music Festival at the Missouri State Fairgrounds in Sedalia, Missouri. Some estimates put the crowd at 350,000 people, which would make this one of the largest music events in history. At another concert, the band opened for the rock band Aerosmith.
Question: Why did they replace Jimmy?
Answer:

Problem: Background: Osceola was named Billy Powell at birth in 1804 in the Creek village of Talisi. now known as Tallassee, Alabama, in current Elmore County. "The people in the town of Tallassee...were mixed-blood Native American/English/Irish/Scottish, and some were black. Billy was all of these."
Context: Through the 1820s and the turn of the decade, American settlers kept up pressure on the US government to remove the Seminole from Florida to make way for their desired agricultural development. In 1832, a few Seminole chiefs signed the Treaty of Payne's Landing, by which they agreed to give up their Florida lands in exchange for lands west of the Mississippi River in Indian Territory. According to legend, Osceola stabbed the treaty with his knife, although there are no contemporary reports of this. Five of the most important Seminole chiefs, including Micanopy of the Alachua Seminole, did not agree to removal. In retaliation, the US Indian agent, Wiley Thompson, declared that those chiefs were deposed from their positions. As US relations with the Seminole deteriorated, Thompson forbade the sale of guns and ammunition to them. Osceola, a young warrior rising to prominence, resented this ban. He felt it equated the Seminole with slaves, who were forbidden to carry arms. Thompson considered Osceola to be a friend and gave him a rifle. Osceola had a habit of barging into Thompson's office and shouting complaints at him. On one occasion Osceola quarreled with Thompson who had the warrior locked up at Fort King for a two nights until he agreed to be more respectful. In order to secure his release, Osceola agreed to sign the Treaty of Payne's Landing and to bring his followers into the fort. After his humiliating imprisonment, Osceola secretly prepared vengeance against Thompson. On December 28, 1835, Osceola, with the same rifle Thompson gave him, killed Wiley Thompson. Osceola and his followers shot six others outside Fort King, while another group of Seminole ambushed and killed a column of US Army, over 100 troops, marching from Fort Brooke to Fort King, in what Americans called the Dade Massacre. These nearly simultaneous attacks began the Second Seminole War.
Question: What attacks caused it?
Answer:
On December 28, 1835, Osceola, with the same rifle Thompson gave him, killed Wiley Thompson.