Did Jesus really die on the cross?

Yes, Jesus really did die on a cross. The scriptures teach this in numerous places. Following are two of them:

"And as they were coming out, they found a man of Cyrene named Simon, whom they pressed into service to bear His cross... 35 And when they had crucified Him, they divided up His garments among themselves, casting lots; 36 and sitting down, they began to keep watch over Him there," (Matt. 27:32,35).
"And they crucified Him, and divided up His garments among themselves, casting lots for them, to decide what each should take. 25 And it was the third hour when they crucified Him," (Mark 15:24-25).
"And when they came to the place called The Skull, there they crucified Him and the criminals, one on the right and the other on the left," (Luke 23:33).
"The soldiers therefore, when they had crucified Jesus, took His outer garments and made four parts, a part to every soldier and also the tunic; now the tunic was seamless, woven in one piece. 24 They said therefore to one another, “Let us not tear it, but cast lots for it, to decide whose it shall be”; that the Scripture might be fulfilled, “They divided My outer garments among them, and for My clothing they cast lots.” 25 Therefore the soldiers did these things. But there were standing by the cross of Jesus His mother, and His mother’s sister, Mary the wife of Clopas, and Mary Magdalene," (John 19:23-25).
“Therefore let all the house of Israel know for certain that God has made Him both Lord and Christ—this Jesus whom you crucified," (Acts 2:36).
"but we preach Christ crucified, to Jews a stumbling block, and to Gentiles foolishness," (1 Cor. 1:22).
"You foolish Galatians, who has bewitched you, before whose eyes Jesus Christ was publicly portrayed as crucified?" (Gal. 3:1).
"and then have fallen away, it is impossible to renew them again to repentance, since they again crucify to themselves the Son of God, and put Him to open shame," (Heb. 6:5).
"And their dead bodies will lie in the street of the great city which mystically is called Sodom and Egypt, where also their Lord was crucified," (Rev. 11:8).

There is dispute on the Greek word for "cross" which is "stauros." It can mean an upright stake or a cross. Therefore, some groups like the Jehovah's Witnesses, say that Jesus died on a vertical stake. But then, others simply deny that Jesus was crucified at all and they claim He died of old age or some other natural sickness. Both of these conjectures are in error according to the New Testament.

First of all, there is a verse in the New Testament that demonstrates Jesus did not die on a vertical stake without a cross bar. If Jesus died on a vertical stake, then His hands would have been placed together over His head, one on top of another. It would be very easy to then take a single nail and drive it through both wrists at the same time. This is how crucifixion was done when victims were crucified in this manner. However, if a person was crucified on a cross, then two nails were required, one for each wrist, since the hands would be spread apart.

If we look at John 20:25 we see that the plural word "nails" is used in reference to Jesus' hands.

"The other disciples therefore were saying to him, "We have seen the Lord!" But he said to them, "Unless I shall see in His hands the imprint of the nails, and put my finger into the place of the nails, and put my hand into His side, I will not believe," (NASB).

The plural form "nails" is used. This means that more than one nail was used upon Jesus' hands. Therefore, we can conclude that the most logical explanation for the plural use of nails is that there is at least two nails, one for each hand that was stretched out from left to right as would be done if Jesus were crucified on a cross. This would mean that the torture stake, or the vertical stake theory would be invalid.

Did Jesus really die on the cross?

According to the gospel accounts, Jesus went through six different trials before He was condemned to die on a cross. Three of the trials were before Gentiles and three were before the Jews. He was repeatedly put before people to be tried and the whole time He was under heavy guard. They knew who Jesus was. So, this excludes the possibility of mistaken identity. Furthermore, it is highly unlikely that the Romans would have crucified a man by mistake. Remember, Jesus had been performing many miracles and was quite well known in the area. Since the Roman soldiers had Him in their possession during the trials, during the beatings, and finally on the way to the cross, the most logical conclusion is that they did not make a mistake and crucified someone else instead of Jesus. Therefore, we can logically conclude that Jesus really did die on a cross.